ci adjustments

[GitMensch]

• ubuntu:
  • only run jobs for "coverage" and "additional warnings" if the main ci build works and use its generated tarball in both cases
  • add two new artifacts: test binaries and windows source
• ubuntu+msys1+msys2+macos:
  • upload config.log after the build - because we may need it to debug build issues
  • always upload the testsuite.log (additional build documentation)
• ubuntu+msys1+msys2:
  • use --with-pkgversion to mark CI binaries
• msys1:
  • GMP url changes, building it again for performance reasons
  • building BDB with all relevant patches from MSYS2
  • drop GC install log step and therefore extra prefix
  • using msys-build instead of building Bison (only necessary for GC4)
  • drop extra CFLAGS previously necessary for local cJSON (fixed in 3.x)
  • enable NIST85 (+ comment-code in case we ever need to skip something there and/or ignoring failing NIST) --> as after last upstream update everything works
  • ci cache adjustment:
    • remove split per matrix
    • split per software, enabling smaller updates
  • use CI tarball like for the minimal build, drop flex+bison
  • drop workflow specific expected failures that now work fine
  • move env to MSYS job
  • resolve env vars by build API instead of runner
• integrate msys1.yml into ubuntu.yml, renaming to build_nightly.yml
• msys2:
  • split NIST + internal testsuite and run the later with less jobs to prevent hanging
  • split between "prepare" and "build" job, with the former generating a full distribution inclusive documentation, and the later having less packages installed, allowing to enable i386 again
• msys2+macos:
  • uploading NIST test results
• msvc:
  • testsuite skip adjustments from the generated testsuite
  • enable building binary package and artifact
  • export dependencies and artifact

temporarily disable (duplicate) PR builds - so do not merge yet