Support Bearer Token

Atlassian Bitbucket (and other Git platform) can support project/repository access token (sample: [Bitbucket](https://support.atlassian.com/bitbucket-cloud/docs/using-project-access-tokens/)), with Header like

```
Authorization: Bearer
```

It is better than User access token, because scope could be more fine delimited.

=> Investiguation usage and implementation should be done in Python components:

```
atlassian-python-api
py-gitea
PyGithub
```

Start by inspecting how authentication is handled through the listed Python components: atlassian-python-api, py-gitea, and PyGithub. Compare their support for project or repository access tokens and identify the integration points in this repository; done means the required Git platforms can use an Authorization Bearer token with appropriately scoped access.

Written by the indexing model from the issue text.