Allow weighting event achievements

[Jamiras]

Allows assigning a point value to an event achievement (1-5 [1=default]). Changes the wording for tiered achievements from "achievements required" to "points required".

SQL to run after upgrade:

UPDATE Achievements SET Points=1 WHERE ID IN (SELECT achievement_id FROM event_achievements);

Then the following command should be run to regenerate the aggregate data for the event games:

sail artisan ra:platform:game:update-metrics 28429,29830,31745,32718,32827,32828,32829,32830,32831,32832,32833,32834,32835,32836,32838,32847