Using FreeIPA for centralized sudo - how to specify ALL commands?

You don't need to make command groups if you want a group of users to be able to execute any command with sudo. You just need a sudo rule that permits all commands, and one should have been created for you by default when you installed FreeIPA.

# ipa sudorule-find All
-------------------
1 Sudo Rule matched
-------------------
  Rule name: All
  Enabled: TRUE
  Host category: all
  Command category: all
  RunAs User category: all
  User Groups: admins
----------------------------
Number of entries returned 1
----------------------------

(If such a rule doesn't exist, create it.)

ipa sudorule-add --cmdcat=all All

Just add the users or groups to this sudo rule that you want to be able to sudo with any command.

ipa sudorule-add-user --groups=admins All

You can also do this from the Web UI if you prefer.