Define check_permissions per act

[Wardormeur]

Instead of having a runtime search for the profiles linked to the act, we can define an act per permission to check
ie : role: pluginName, cmd: 'checkPermissions', ref: cmdName
It should support multiple domains/subpatterns, so that ref may be an object to avoid having to redefine ref depending on the nesting
It must also keep the fact that a missing act is allowed if not found (overwrite default$ from seneca to return {allowed:true} when the error is "act_not_found")