FEATURE/SERVICE: Create Github Pull Request Integration

[boyter]

Pie in the sky thinking here, but it would be nice to add scc integration into GitHub for pull requests. Features I would like to see form this included below.

• Size of the PR relative to other PR's for the project and compared globally to similar projects
• Estimate the complexity as well in the above such that large changes of low complexity IE adding a JSON file are flagged as such
• Give an idea of what level of effort the PR should take

I can see the above being very useful when it comes to reviewing PR's giving the reviewer a very quick idea of how long they might need.

Note this sits outside scc itself, but similar to how GitHub badges work, related to the project but not part of it itself.

[boyter]

OK beta version implemented and installed on this repo. Lets see if anyone makes any PR's and observe how it works.