BLD: add libquadmath to licences and other tweaks (#24753)

[charris]

Backport of #24753.

As pointed out in MacPython/openblas-libs#114, we are bundling libquadmath which is licensed differently than the rest of the gcc runtimes. This PR

• adds its license, which is complicated. Most of it is copyright "Sun, with use freely granted". But there are a few files licensed under the LGPL2.0 and LGPL2.1, and even one file that is "Public domain". I am not sure what the implications are.
• Change the canonical location of OpenBlas to https://github.com/OpenMathLib/OpenBLAS
• Add OpenBLAS and LAPACK licences to macos, they were missing?
• Remove the msvc runtime licenses from windows, we do not bundle it (anymore?)
• tweak the locations of the bundles in the site-packages tree.

I think this should be backported. While #24613 to use Accelerate for macos-arm64 was backported, I see the 1.26 wheels are still using OpenBLAS, so the license should not change.

Other improvements:

• use SPDX short specifiers, fixes from review
• only use openblas_support.make_init() in CI, fix paths
• fix license concatenation for wheels we distribute

Closes gh-24764