add PersonalAccessTokenApi #934

[katrinSaleschus]

Fixes #934

[jmini]

Usually we mention the endpoint called in the javadoc (easier to find later), can you add something like:

     * <pre><code>GitLab Endpoint: POST /personal_access_tokens/self/rotate</code></pre>

[jmini]

Please add a json file in src/test/resources/org/gitlab4j/api and a test case in TestGitLabApiBeans for this new model class

[jmini]

I have rebased the source branch of this PR (addrotatepersonalaccesstoken in the katrinsaleschus fork) on top of main of this repo:

git rebase --onto origin/main db1a7585eee4f77b53fe236950d113816ed9502b
git push katrinsaleschus HEAD:addrotatepersonalaccesstoken --force

Be aware that your local branch addrotatepersonalaccesstoken has diverged with the one on the GitHub.

If you need to do one more changes on this branch:
I recommend to use git fetch and git reset --hard origin/addrotatepersonalaccesstoken (assuming your local origin is pointing to the katrinsaleschus fork on GitHub) before doing any local modifications instead of git pull.

I have changed the target branch of this PR to be main

I have added the missing test and did the necessary fixes

[jmini]

Merged to main and 6.x. Thank you for this contribution 🎉