Gitlab pr bot

[hyqshr]

GitLab pr-review-bot

Express app that process GitLab MR webhook request and generate PR

This function will be called when a GitLab MR event is received, then

1. Fetch the diffs files in the MR
2. Fetch the original file content for each changed file
3. Call the Greptile API to comments (individual comment and overall comment)
4. Post the generated comments to the MR

Note, right now individual comment is not working (function postMultipleComments) since the code did not get new_line and old_line correctly