[JENKINS-70897] Add support for personal access token authentication

[Gagarmel]

JENKINS-70897 - summarize pull request in one line

On Bitbucket Datacenter/Cloud and Azure it is required to use personal access tokens instead of username/password authentication.

Resolves jenkinsci/bitbucket-branch-source-plugin#716
Requires jenkinsci/git-client-plugin/pull/1104

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[habazie]

Please kindly add these changes.