[#1137] Sync Trac ticket with GitHub pull request state.

Problem description
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I don't like doing manual sync between github and trac.

So here comes the magic part :sparkler: 


Changes description
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Implemented the 'needs-review' and 'needs-changes' comment synchronization described here:

https://trac.chevah.com:10443/wiki/Development/Process/BranchWorkflow

When a pull request is ready for review, we will just post a comment containing **needs-review**

Trac tickets are no longer closed by PQM, but at mergeinto master. This means that we can also have automatic ticket closing for code which does not go to PQM (ex: salt-master, agent-1.5)


How to test
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reviewers @lgheorghiu

removed reviewers alibotean cracknel 

I tried not to create yet another repo on GitHub so the code for this is hosted on internal network:
https://trac.chevah.com:10443/browser/github-hooks-server

This ticket is posted on `seesaw` our playground repo so feel free to hit this pull request with comments and check how they are synced with Trac.