adding PK to table encryption

adding auto increment/PK to table files_trash

adding PK to table ldap_user_mapping and ldap_group_members

adding PK to table ldap_group_mapping

truncate permissions table to allow smooth creation of primary key

adding unit test for creating an auto increment column on a table which already contains data

remove unneeded table files_trashsizes

fix unit test

no need to truncate *PREFIX*permissions

On Oracle adding auto increment columns is not working out of the box - Oracle migrations are to be done manually
Merge pull request #8253 from owncloud/pk-on-all-tables-master

Primary keys on all tables master