don't handle public share keys in lib/public/share.php but in apps/files_encryption/lib/util.php instead

use preShare hook only to check if all pub keys are available and the postShare hook to finaly update the shareKeys if the file was shared successfully

NOTE: only encryption work atm

Made sure new user being shared to is added to array of sharing users

Switched it for post_share hook in encryption hooks
Stop a file from being shared if the encryption procedure fails for any users

Added success/fail feedback to personal settings functions
Improved look/layout of personal settings page
Fixed misplaced plain text in ajax scripts

Made encryptAll() (file migration for unencrypted + legacy encrypted files) run only on first login for each user (status stored in DB)
Made recoveryAdmin user member of 'admin' user group automatically
Set recoveryadmin settings to only display on user settings if enabled by an admin
Updated encryption db xml schema