Add delete cascade for events

[bux]

New Dump from a MariaDB database with an added FK Constraint on replayId.

The goal was to make deleting events easier. Now one just needs to delete the replay and the associated events get deleted automatically.

And I've changed the id column of the replays table to be unsigned (just like the replayId column of the events table)

Needed to change order of tables for the constraint to properly/reliably work.