Move libpython.so to another output

[isuruf]

Maybe libpython-devel and merge that with libpython-static.
This shared library is unneeded 99.9% of the time.

Let's do this for python 3.15

cc @mgorny

[isuruf]

Looking at #842 and the tests, we have to manually delete the other if both exist. So, let's use libpython for the shared library and libpython-static for the static library.

[mgorny]

What about the *-embed.pc files? They're the same for both. Should I keep them in python (where they're effectively nonfunctional due to missing libs), or copy to both?

[isuruf]

We can keep them in python since they are the same for both.