[Python] Improve Python interop usability. (#22104)
- Define `version` and `versionInfo` computed properties on `PythonInterface`
for convenience.
- Rename `numpy.ndarray` initializer to `init?(numpy:)`.
- `init?(numpy:)` is a bit shorter than the previous `init?(numpyArray:)`.
Using a labelless initializer is problematic because it causes type inference
problems due to implicit conversions.
