Create more useful indexes and also let the columns which are supposed to be joined have the same collation and charset.

Don't encrypt passwords on reading but when writing into the DB to speed up dramatically cases where the logins are only read, eg the valdiation.

Formally this is possible (and should be), although it has no effect ('monitor-group'-persons have automatically all booklets of the group as in demo mode). Doing so lead to a recursion-error; this gets fixed by this commit.

https://github.com/iqb-berlin/testcenter-backend/issues/241

Fix Zip-File Upload: The Validator is not strict about Version-Sytax in Filenames: (player-4.html matches player-4.0.0.html). This was not correctly implemented in the validation during upload. As a result when units with their corresponding resources, the units got rejected although everything was correct when the reference to the player was not matching extacly the filename.

Use ITCR.ZIP (= IQB Testcenter Resource) as extension for Resource-Package instead of vopgk which was only a working title.

Fix package-extraction-dir file deletion.

Drop the idea of an index.json file in the package.

The DB-based version had one big disadvantage: The DB has no problem with many or big files, BUT MySQL does not support output as stream, so we have to load the full file into a PHP-Variable and thus into the memory. This is not nice, streaming from actual files is better.

Only flash Broadcasting-Service on initialize when it is running (to avoid confusing message in log).

When it's not running it's either not intended to run or rebooting. In both cases no flashing is required.

https://github.com/iqb-berlin/testcenter-backend/issues/239