Modular dependency problems encountered while installing Red Hat Capsule 6.15

Issue

• The following error was encountered while installing a new Red Hat Capsule 6.15 server:

  Problem 1: module satellite-capsule:el8:61520240418172655:980ee624.x86_64 from satellite-capsule-6.15-for-rhel-8-x86_64-rpms requires module(postgresql:12), but none of the providers can be installed
  - module postgresql:10:8020020200825115746:4cda2c84.x86_64 from rhel-8-for-x86_64-appstream-rpms conflicts with module(postgresql:12) provided by postgresql:12:8010120191120141335:e4e244f9.x86_64 from rhel-8-for-x86_64-appstream-rpms
  - module postgresql:12:8010120191120141335:e4e244f9.x86_64 from rhel-8-for-x86_64-appstream-rpms conflicts with module(postgresql:10) provided by postgresql:10:8020020200825115746:4cda2c84.x86_64 from rhel-8-for-x86_64-appstream-rpms
  Problem 5: module satellite-capsule:el8:61520240903125913:30aa3ae0.x86_64 from satellite-capsule-6.15-for-rhel-8-x86_64-rpms requires module(postgresql:12), but none of the providers can be installed
  

  and while proceeding with the troubleshooting as per B.2. PostgreSQL, the following error was encountered:

  # dnf install postgresql-upgrade
  .
  .
  Complete!
  
  # postgresql-setup --upgrade
  ERROR: config file /var/lib/pgsql/data/postgresql.conf is not readable or does not exist
  FATAL: Old cluster in '/var/lib/pgsql/data' does not seem to be initialized