[WIP] opencv: update to 5.0.0 [skip ci] [ci skip] [no ci]

[zlice]

Testing the changes

• I tested the changes in this PR: briefly

ffmpeg9 #62550

Local build testing

• I built this PR locally for my native architecture, x86_64
• I built this PR locally for these architectures (if supported. mark crossbuilds):
  • aarch64-musl

broken

gmic is a royal pain. i don't know how other distro's have gotten this to build. finally got a half gnu-make + half cmake/ninja for qt/gimp stuff to go. end up with some conflict between qt5 (for zart) and opencv5 where the c-macro is namestepped from for X11 Status and flubs, and then trying to move things around for that seems to make qt5 go fubar.

everything else appears to build for arm64-musl