Fix for clarifying the need for a user with username "admin" (#19)

This step is mandatory so as to access the OpenSlice Web UI. To add an OpenSlice admin user you must:

- Navigate to realm Openslice > Users > Add user

- Set ```admin``` username

- Set a password

- Upon creation, navigate to Role Mappings and add ADMIN to Assigned Roles list

> That user is different from the Keycloak admin user. It is required to login and browse the OpenSlice Web UI. The Role ADMIN guarantee full access through the OpenSlice UI, thus such a user is always required.

> You may have multiple ADMIN role users, but you must have at least one with ```admin``` username.

### Keycloak at localhost

> **This is an important step if you run Keycloak on localhost!**

#### 2. Add an OpenSlice admin user

This step is mandatory so as to access the OpenSlice Web UI. To add an OpenSlice admin user you must:

- Navigate to realm Openslice > Users > Add user

- Set ```admin``` username

- Set a password

- Upon creation, navigate to Role Mappings and add ADMIN to Assigned Roles list

> That user is different from the Keycloak admin user. It is required to login and browse the OpenSlice Web UI. The Role ADMIN guarantee full access through the OpenSlice UI, thus such a user is always required.

> You may have multiple ADMIN role users, but you must have at least one with ```admin``` username.

### NFV Orchestrator Configuration

After successfully deploying and configuring OpenSlice, you may configure its environment (e.g. the NFVO) that will facilitate the deployment of NFV artifacts.

      - Jenkins Helm Installation aaS : ./service_design/examples/jenkins_helm_install_aas/jenkins_helm_install_aas.md

      - Monitoring aaS: ./service_design/examples/monitoring_aas/monitoring_aas.md

  - Service Ordering:

    - Ordering Services from catalogs: ./service_ordering/ordering_services.md

    - Ordering Services from Catalogs: ./service_ordering/ordering_services.md

  # - Testing services:

  #   - Testing Specification: ./testing_services/test_spec.md

  #   - Testing Catalogs: ./testing_services/test_catalogs.md