This reverts commit e19b3a87.

- the file/folder's permission is now stored in the file cache
- BackGroundWatcher has been removed - this has meanwhile be replaced by occ files:scan which can be executed in a cron jobs
- increase version to trigger database migration

# The first commit's message is:

adding tests for long paths
increment path field in database up to 4000 (maximum for Oracle - otherwise we could use php's 4096)
increment version to trigger database migration
adding unit test for too long path

# This is the 2nd commit message:

fix too long path

improved file size calculation and speeds