Mass Issues Across all Repos in an org

[SeanKilleen]

Supports #89.

• Do the thing
• Cleanup: extract classes into files
• Cleanup: R#

[SeanKilleen]

Next up -- just realized I'll be potentially creating 200+ calls to GitHub's service. We'll need to batch them and run the batches in parallel, hopefully without triggering an abuse mechanism.

So I'll probably create a runner and use SemaphoreSlim because that seems at least able to be reasoned about. Reference: https://stackoverflow.com/questions/42511104/run-asynchronous-tasks-in-batch

[SeanKilleen]

Tested this in another, much smaller, organization and it did what I wanted it to do. 👍

This PR can be merged and we'll continue the work.