[Milestone] Formulas

[ale-cota]

Opportunity

Other competitors support the creation of formulas based on metrics (e.g. a/b, (a-b)/b, etc.). This has become a table stakes feature that users have come to accept and is also one of the main blockers for transitioning internally from Datadog to Sentry.

Solution

• Add support for basic arithmetic operations and use of brackets in order to express formulas: +, -, *, /, (, ).
• Introduce use of formulas in the Metrics explorer page and metrics based Dashboard widgets (already supported for other datasets)

Know limitations

• In the first iteration it will only be possible to use queries that access the same namespace and metric type in one formular.

Milestones

### Formulas in Metrics Page
- [ ] https://github.com/getsentry/sentry/issues/64543
- [ ] https://github.com/getsentry/sentry/issues/64544
- [ ] https://github.com/getsentry/sentry/issues/64776
- [ ] https://github.com/getsentry/sentry/issues/64777

### Investigation
- [ ] https://github.com/getsentry/sentry/issues/64545
- [ ] https://github.com/getsentry/sentry/issues/64454
- [ ] https://github.com/getsentry/sentry/issues/64989

### Feature refinement
- [ ] https://github.com/getsentry/sentry/issues/64778
- [ ] https://github.com/getsentry/sentry/issues/64779