Add guidance for optimized live_update workflow with more frameworks

[milas]

This was prompted by a user request to add a Python + fastapi example.

There's generally many popular frameworks for any given language, and it's likely impractical to maintain full examples for each. However, we could probably offer some guidance around common options/flags (e.g. most Python frameworks can run in a dev server mode that automatically picks up changes to code) for the most popular frameworks.

If there's a framework (not necessarily Python!) you're struggling to optimize your Tiltfile + live_update for, add a comment here with some details!