ECMS-6016 : css leak across tenants

Conflicts:
	packaging/wcm/webapp/src/main/webapp/groovy/portal/webui/workspace/UIPortalApplication.gtmpl
ECMS-6016 : css leak across tenants - change skin module name pattern
Merge branch 'feature/stabilization'
Merge branch 'master' into feature/stabilization
Merge commit '973111abfb07175b845002d1f35d863136fea6f2' into HEAD