Add notes on github tricks for workflow (post vscodepocolypse)

[jlperla]

Might want to focus on vscode extension, etc. and wait until we have pushed that GUI more.

Show the idea of an issue associated with a PR.
Create issues that would have a coherent self of changes associated with it, so all branches are easy to track.

Also, describe rebasing onto master and merge conflicts. But if you don't have PRs open too long, it genreally isn't a problem. Point to merge-conflict resoluiton in vscode as well.