Python images need to support MUSL-based systems (alpine)

The `python:xx-alpine` images require Python debugger packages setup for musl. There doesn't seem to be any image metadata to identify musl/alpine-based images, so `skaffold debug` can't select a musl-specific image. So this seems to be something that has to be detected at runtime with the new python launcher.

Alpine images:
- /etc/os-release has ID=alpine
- /lib/ld-musl-x86_64.so.1
- /lib/libc.musl-x86_64.so.1
- /lib/libapk.so.3.12.0
- no /lib64

This [answer](https://unix.stackexchange.com/a/605854/65738) cites existence of /lib/ld-musl-* and /lib/libc.musl-*.