✨ Allow selecting data sources

[bradystroud]

Right now all data sources get pumped into GPT

### Tasks
- [ ] In the UI add some checkboxes (or something better) to allow users to enable/disable data sources by default
- [ ] Everything on by default
- [ ] API endpoint shoud support this if #22 is done

e.g.

• [x] emails
• [x] appointments
• [ ] teams calls