CI: Use source tarball instead of cloning submodules

[Biswa96]

• Changes:

  • Linux docker and macos builds now depend on upload-src job.
  • Download the source tarball from upload-src instead of checking out.
  • Install tar and xz in fedora and opensuse.

• Pros:

  • Now submodules are cloned only once.
  • This reduces total CI time.
  • Building from the released source tarball verifies it.

[nmeum]

Thanks!