feat(bitbucket-server): support bearer token authentication

[jaecktec]

Add support for project/repository http access token

Changes

allowed token authentication by passing the authentication to the rest api and simple-git as extra-header

Context

fixes https://github.com/renovatebot/renovate/issues/14900

Documentation (please check one with an [x])

• [ ] I have updated the documentation, or
• [x] No documentation update is required

How I've tested my work (please select one)

I have verified these changes via:

• [ ] Code inspection only, or
• [ ] Newly added/modified unit tests, or
• [x] No unit tests but ran on a real repository, or
• [ ] Both unit tests + ran on a real repository

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[simschla]

I'm confused: is this PR closed because the feature will not be added or is it not possible?

[viceice]

it seems the author is not able to implement the suggestions or can't sign the cla

[jaecktec]

I can't find the suggested places required to be changed. And most of the changes had the 'revert' comment, so basically the entire PR