Instead of old `addManuallyAddedInterpreter` we now have two functions: one that requires system python and one that doesn't.
Both functions register system python if provided, but the latter one accepts any python (venv included).
Various "selectors" use these functions.
We also make sure no non-system python is set to `baseInterpreters`: base are always system!
As a bonus, we show "system" or "virtual env" title near interpreter.
It now checks that python is system (see `ensureSystemPython`).
Non-system pythons are never reported, and `registerSystemPython` also returns an error for non-system pythons
We need `execGetBoolFromStdout` for the further changes
Merge-request: IJ-MR-182415
Merged-by: Ilya Kazakevich <ilya.kazakevich@jetbrains.com>
GitOrigin-RevId: 2950f5f0cd2745c12987a92e40774d366568f312
Use `ExecService` `api.kt` to exec any binary and extensions from `execService.python/api.kt` for python-specific things (i.e helpers)
GitOrigin-RevId: bb217798a9d1ee886c4b12220ec1f66a5ef08336
