Refs #4478 - prebuild localized apipie cache

Requires https://github.com/theforeman/foreman/pull/1428 to get merged.
Documentation for resources is built during build time. Docs for Index is build in posttrans phase as we need foreman plugins to be present.
Check descritpion of the related foreman PR theforeman/foreman#1428  for more deatils . In short to minimize time necessary for building apipie:cache we pre-build part of the cache during the build time. The second apipie:cache call in %posttrans that builds  the rest of the cache is run after installation/update when hopefully also the foreman plugins are in place