Simplify the spec file
    
    - ansible-core is in rhel-8.6 and newer, but not installable
      in buildroot as it depended on modular Python.
      It has been installable at buildtime in 8.8 and newer.
      Considering this fact, eliminate with/without ansible condition
      and use ansible-galaxy to build collection in the Fedora builds.
    - Move the ansible_collection_* macros to ansible-packaging.inc,
      that is for maintaining the compatibility with ansible-packaging.
    - Move a rhel specific Provides to ansible-packaging.inc.