## Summary
Currently you can either run a single service or all-in-one mode. This
PR adds support for running any 2 or 3 services together. For example
`services: authorize,proxy`.
I think I updated the conditions to make sense, but there's some risk
here as there may have been some assumptions in places I'm overlooking.
## Related issues
-
[ENG-2485](https://linear.app/pomerium/issue/ENG-2485/core-support-running-multiple-but-not-all-services)
## Checklist
- [x] reference any related issues
- [x] updated unit tests
- [x] add appropriate label (`enhancement`, `bug`, `breaking`,
`dependencies`, `ci`)
- [x] ready for review
