Allow to configure userContent url
Clear filesystem in clearEnv() *after* config has been reset
Allow to register instance with service-manager, allow to unregister services
Make usercontent_temp::create() more robust
Add namespace-able url+filesystem config to usercontent-file
Pass usercontent url list to client, use in cm.getUrlUserContent()
Merge branch 'master' of github.com:cargomedia/CM into issue-1233

Conflicts:
	library/CM/App.php
Introduce user-content service
Adjust config
Introduce service-manager-aware trait, make sure to set serviceManager when registering service as instance
User usercontent-service in usercontent-file
Add docu for manager-aware trait
Allow to pass service-manager to temp usercontent file
Validate usercontent service config
Merge pull request #1233 from njam/issue-1233

Allow to configure userContent url