problems

1. Session table is split in two tables (session / sessionInternalUniqId) which are synced in code. They should be combined
2. remove direct session access so that the authenticated user is kept just as user id in session → DONE but must be rechecked
3. change session table to in memory table to improve performance. This should bed done with https://jira.translate5.net/browse/TRANSLATE-3574 in the next step. Reason is, each worker currently writes entry in the session which can easy lead to full table and memory limits. Until we refactor the workers, this will stay as it is.
4. Check if really the whole userdata must be in the session, since only the userId is ncessary to load the user on Session Loading

Session handling got to complicated through the years and is probably responsible for a lot of not authenticated errors that we have via theRootCause.

Therefore it should be redone.