READme changes

For that purpose NetApps play 2 different roles when interacting with CAPIF:

- **Invoker**: a NetApp acting as an Invoker is responsible for consuming APIs exposed by other services. This role represents an external application or service that  calls the 3GPP northbound APIs to utilize the network’s functionalities.

- **Provider**: a NetApp acting as a Provider is responsible for exposing its own APIs for use by Invokers. This role represents an entity that offers services through APIs, making them available to other external applications or Invokers.

- **Provider**: a NetApp acting as a Provider is responsible for exposing its own APIs//services for use by Invokers. This role represents an entity that offers services through APIs, making them available to other external applications or Invokers.

**NetApps developers are the target users of OpenCAPIF SDK.**

- [CAPIF Publish API specification](https://github.com/jdegre/5GC_APIs/blob/Rel-18/TS29222_CAPIF_Publish_Service_API.yaml) 

- [CAPIF Security API specification](https://github.com/jdegre/5GC_APIs/blob/Rel-18/TS29222_CAPIF_Security_API.yaml)

NOTE: In the [3GPP Technical Specification (TS) 29.222 V18.5.0 Common API Framework for 3GPP Northbound APIs](https://www.etsi.org/deliver/etsi_ts/129200_129299/129222/18.05.00_60/ts_129222v180500p.pdf) the `service` concept is understood as equal as the `API` concept.

## OpenCAPIF SDK requirements

To leverage the OpenCAPIF SDK, you must have a registered user in the target CAPIF instance. **Please contact the administrator to obtain the necessary predefined credentials (username and password).**

# Netapp developer path

The NetApp Developer Path guides you through building and integrating NetApps using CAPIF. This path is divided into two key sections: Invoker NetApp and Provider NetApp. Each section covers the essential flow and functions for developing NetApps interaction with CAPIF, whether you’re acting as an invoker consuming services or a provider offering them. By following this path, developers will gain a comprehensive understanding of how to effectively use the SDK within the CAPIF ecosystem.

Here is a code sample of the implementation of this hole [Invoker-Netapp](./netapp-samples/netapp-invoker-sample/netapp-invoker.py) sample.

1. **Create an Invoker object:** \

   Initialize the invoker by creating an instance of the `CAPIFInvokerConnector` class, passing the required configuration file:

   ```python

      invoker = CAPIFInvokerConnector(config_file=utilities.get_config_file())

   ```

2. **Onboard the Invoker**: \

   Register the invoker with the CAPIF system to enable access to APIs:

   ```python

      invoker.onboard_invoker()

   ```

3.	**Create a Service Discoverer object:** \

  Initialize the service discovery mechanism to search for available services:

    ```python

      service_discoverer = ServiceDiscoverer(config_file=utilities.get_config_file())

    ```

4.	**Discover available services:** \

  Use the discover() method to retrieve a list of available APIs:

  DISCLAIMER: if it's the first time the user runs discover() it will appear a warning alert like this

      WARNING - Received 404 error, redirecting to register security service

    ```python

      service_discoverer.discover()

    ```

5.	**Retrieve security tokens:** \

  Use the get_tokens() method to obtain the necessary tokens for authenticating API requests: 

    ```python

      invoker.get_tokens()

    ```

Then all information for using the available APIs would be at Capif_api_security_context_details.json 

This file would be placed in the invoker_folder path, more specifically in the folder that corresponds of the capif_username used in the config_file.

Here is a sample of this Capif_api_security_context_details [file](./samples/capif_api_security_context_details-sample.json) 

This image highlights Invoker path using SDK code:

![INVOKER_PATH](./doc/images/Flujo%20completo-INVOKER%20PATH.jpg)

### Important information for Invoker consumer

In the `invoker_folder`, it will be located several folders with each `capif_username` it has been onboarded as a provider. For each folder, it could be found:

- `Capif_api_security_context_details.json`: This file contains the information of the invoker. It will contain:

    1. The `api_invoker_id`.

    2. If the Service Discovery Functionality has already been used , it will be found all the available APIs with their information.

    3. If the Service Get Token functionality has already been used , it will be found the access token for using the APIs that has already been discovered.

## Provider NetApp

A NetApp development running as a Provider would typically follow this process step by step, making use of the SDK:

Here is a sample of the implementation of this hole [Provider-Netapp](./netapp-samples/netapp-provider-sample/netapp-provider.py)

1. **Create a Provider object:** \

   Initialize the provider by creating an instance of the `CAPIFProviderConnector` class, passing the required configuration file:

    ```

3. **Prepare API details:** \

   Locate the provider API details in the provider_folder path, more specifically in the username folder. Choose the APF (Application Programming Function) and AEFs (Application Enabling Functions) identifiers, and fulfil the publish_req structure and the api_description_path:

   Locate the provider API details in the provider_folder path, more specifically in the username folder. Choose the APF (API Publishing Function) and AEFs (API Exposing Function) identifiers, and fulfil the publish_req structure and the api_description_path:

<p align="center">

  <img src="./doc/images/capif-provider-details-example.png" alt="example" width="400"/>

    2. If you have already used the Service Discovery Functionality, you will find all the available APIs with their information.

    3. If you have already used the Service Get Token functionality, you will find your access token for using the APIs you have already discovered.

In the `provider_folder`, it will be located several folders with each `capif_username` that has already been onboarded  as a provider, for each folder it is created by SDK this files:

- `Capif_provider_details.json` : Contains all the APFs and AEFs ids that have already onboarded with this capif_username

- `CAPIF_<api_name><API_id>.json` : If it's already published or updated an API, It will be available a copy of the last payload.

- `Service_received.json` : If it's already used the get an api or get all apis functionality, It will be available the response to the request.

- `Published-Apis.json` : Contains the currently published APIs with their ApiId