We'll soon be needing a more feature-complete external API. To make way
for this, I'm moving some files around so:
- We can more easily create new versions of our external API
- The file structure of our internal API is more homogeneous
These changes are quite opinionated, but IMO in any case they're better
than the chaotic structure we have now.
### Changes 🏗️
- Move `backend/server` -> `backend/api`
- Move `backend/server/routers` + `backend/server/v2` ->
`backend/api/features`
- Change absolute sibling imports to relative imports
- Move `backend/server/v2/AutoMod` -> `backend/executor/automod`
- Combine `backend/server/routers/analytics_*test.py` ->
`backend/api/features/analytics_test.py`
- Sort OpenAPI spec file
### Checklist 📋
#### For code changes:
- [x] I have clearly listed my changes in the PR description
- [x] I have made a test plan
- [x] I have tested my changes according to the test plan:
- CI tests
- [x] Clicking around in the app -> no obvious breakage
