Minimal Interesting Binder

[bollwyvl]

Having a binder that does... anything... would be really useful.

Once #29 is good to go, I'll be happy to do the work to add a read-only AnonGitHubManager which would let you at least look at something (until you ran out of requests).

Some deltas here:

• this manager would require a starting point (e.g. a specific org or repo)
  • but we probably want that anyway
• carefully managing n+1 queries (don't list files/discussions until needed)
  • probably need to do that anyway
• add a Router endpoint that avoids many queries and gets you to the good stuff

From a re-use perspective, if all a project had to do was...

# requirements.txt
jupyterlab-pullrequests
# diff-match-patch

And then a binder URL so that, e.g. jupyterlab/jupyterlab PR 1234 was:

GET https://mybinder.org/v2/gh/jupyterlab/jupyterlab/HEAD?urlpath=lab/prs/agh/jupyterlab/jupyterlab/1234

...to bop you right into the PR overview. That could then happily grab the list of files and the discussion, and you would most likely be able to view a lot of what you needed before you hit the budget.

[bollwyvl]

I'm planning to take a go at this, hopefully should have something up soon!