biblioteq: update to 2024.06.30.

[Rutpiv]

Testing the changes

• I tested the changes in this PR: briefly

Local build testing

• I built this PR locally for my native architecture, (x86_64-glibc)
• I built this PR locally for these architectures using specific masterdirs:
  • x86_64-musl
  • i686
• I built this PR locally for these architectures (crossbuilds):
  • aarch64
  • aarch64-musl
  • armv7l
  • armv7l-musl
  • armv6l
  • armv6l-musl

Migration to Qt6 for x86_64 and i686

I have migrated the BiblioteQ package to use Qt6 for x86_64 (both musl and glibc) and i686 architectures. The ARM builds remain on Qt5, and I have also added configuration support for PPC, although I have not tested the migration on architectures other than my own.