added private share api
add a "helper" and a "hooks" class. Move constants needed by multiple classes
to a "constants" class
remove prepFileTarget() seems that it is no longer in use
seperate creation of select statement
seperate transformDBResults
use  variable
don't assign variables in if conditions
seperate formatResults()
always return an array
add todo
don't assign variables in if condition
fix path creation for re-shares, issue #7662
finally fix the paths for the OCS Share API
Merge pull request #7879 from owncloud/sharing_cleanup_public_api

sharing api cleanup, first step