This is a partial backport of MDL-73270 to ensure that the
check_xmlrpc_usage custom check is present in all the supported
branches and it's applied to all branches able to run php80:
- MOODLE_311_STABLE
- MOODLE_400_STABLE
- master (aka, 4.1 and up)
Note that the whole patch has not been backported, only the
environmental check (xml file and check implementation).