MUC: Don't default component admins to being room owners
This change has various technical and social benefits. If ownership of a MUC
is really needed, it can be gained using the 'Set affiliation' ad-hoc command
or prosodyctl shell.
Example client incompatibility with the old behaviour:
- https://github.com/monal-im/Monal/issues/1085
module:log("error", "mod_pep_plus has been renamed to mod_pep, please update your config file. Auto-loading mod_pep...");
module:depends("pep");