We now use `SystemPythonService` to look for system pythons and validate new pythons against it.
GitOrigin-RevId: c06201cd03f7e1cb060a44c4578dd71f8bb05df6
See `README.txt`.
The "Python Services" is a new API for PyCharm execution subsystem.
The idea is to build the following mental model:
1. If you need an API -- there should be a service.
2. Each service has a showcase in "tests" root so you can see how it works in real life.
3. Code against interfaces.
4. Only link against those modules/services you really need.
5. No UI, no leaky abstractions in services.
This change introduces two services:
1. `SystemPythonService` to work with CPythons installed on OS.
GitOrigin-RevId: b07df246d1510a02c060fa7a929cf134879c7677
