fix ocs private data handeling.
fix ocs private data handeling.

 - return the app in privateDataGet
 - implement privateDataDelete
 - split key-value storage from ocs parsing/output so plugins can use it for storage to

lrytz/core,Ardinis/server,IljaN/core,pmattern/server,xx621998xx/server,jbicha/server,whitekiba/server,endsguy/server,andreas-p/nextcloud-server,Ardinis/server,bluelml/core,andreas-p/nextcloud-server,pollopolea/core,pmattern/server,michaelletzgus/nextcloud-server,lrytz/core,xx621998xx/server,pmattern/server,cernbox/core,whitekiba/server,jbicha/server,michaelletzgus/nextcloud-server,sharidas/core,pixelipo/server,sharidas/core,owncloud/core,Ardinis/server,pollopolea/core,michaelletzgus/nextcloud-server,xx621998xx/server,endsguy/server,andreas-p/nextcloud-server,bluelml/core,owncloud/core,lrytz/core,whitekiba/server,lrytz/core,pollopolea/core,Ardinis/server,owncloud/core,endsguy/server,cernbox/core,pixelipo/server,IljaN/core,Ardinis/server,sharidas/core,whitekiba/server,nextcloud/server,sharidas/core,cernbox/core,bluelml/core,pollopolea/core,pollopolea/core,pmattern/server,cernbox/core,pixelipo/server,IljaN/core,nextcloud/server,nextcloud/server,jbicha/server,xx621998xx/server,xx621998xx/server,jbicha/server,bluelml/core,pixelipo/server,lrytz/core,nextcloud/server,andreas-p/nextcloud-server,jbicha/server,phil-davis/core,cernbox/core,andreas-p/nextcloud-server,owncloud/core,sharidas/core,bluelml/core,endsguy/server,pmattern/server,michaelletzgus/nextcloud-server,owncloud/core,IljaN/core,endsguy/server,pixelipo/server,IljaN/core,whitekiba/server