utils/build-galaxy-release.sh: Create module action group

The module action group <collection-prefix>.modules is created
automatically while building the galaxy release.

The action group can be used for module_defaults in this way:

    module_defauls:
      group/<collection-prefix>.modules:
        ipaadmin_password: SomeADMINpassword

Example:

    module_defaults:
      group/freeipa.ansible_freeipa.modules:
        ipaadmin_password: SomeADMINpassword
        ipaapi_context: "{{ ipa_context | default(omit) }}"
    collections:
    - freeipa.ansible_freeipa