add: new example using personal access tokens.

[swade1987]

Description

This PR provides the following:

• An example of bootstrapping a GitHub repository using a personal access token (PAT)
• Updating the main README to include a contribution and community section

Motivation and Context

Fixes #633

How has this been tested?

• Have you added an acceptance test for the functionality being added?
• Have you run the acceptance tests on this branch?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Documentation

• I have updated the documentation (if required) with make docs

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have signed-off my commits with git commit -s

Community Note

• Please vote on this issue by adding a 👍 reaction to the original issue to help the community and maintainers prioritise this request
• If you are interested in working on this issue or have submitted a pull request, please leave a comment

[stefanprodan]

I would rename the example dir to github-via-pat

[stefanprodan]

LGTM

Thanks @swade1987 🏅