docs: update contributing guidelines and add issue template

## Description

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## Scope

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## Deliverables

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## Acceptance criteria

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Thank you for considering contributing to the Federation Manager project!  

We welcome contributions from the community to help improve and evolve this open-source implementation.

The [OpenOP contributing guide](https://oop.etsi.org/documentation/latest/community/contribute/code/)

describes how to contribute to every OpenOP repository: the workflow, branches

and commits, merge requests, review, and the definition of done. Read it first.

## How to Contribute

1. **Fork the repository** and create your branch from `main`.

1. **Fork the repository** and create your branch from `develop`.

2. **Write clear, concise code** that follows Python best practices.

3. **Include tests** if you add new functionality or fix a bug.

4. **Update documentation** as needed to reflect your changes.

5. **Submit a pull request** with a clear description of your changes.

4. **Update documentation**: the architecture specification first, in its own merge request, and this

   repository's documentation in your merge request.

5. **Open a merge request** against `develop` with a clear description of your changes.

## Local checks

## Code Guidelines

- Follow [PEP8](https://peps.python.org/pep-0008/) coding style.

- Write meaningful commit messages.

- Keep pull requests focused and small when possible.

- Write commit messages in the [Conventional Commits](https://www.conventionalcommits.org/) format.

- Keep merge requests focused and small when possible.

- Document public methods and classes using docstrings.

## Reporting Issues

If you find a bug or have a feature request, please open an issue using the [Issue Tracker](../../issues).

If you find a bug or have a feature request, please open an issue using the [Issue Tracker](../../issues)

and the issue template.

When reporting a bug, please include:

- A clear description of the problem

## Community Standards

We are committed to providing a welcoming and respectful environment for all contributors.

All contributors follow the OpenOP [Code of Conduct](https://oop.etsi.org/legal/code-of-conduct/).

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