Merge pull request 'O.N.G.E.K.I.: Card Maker fixes, improvements and bug fixes' (#25) from Dniel97/artemis:cardmaker_ongeki_fix into develop

Reviewed-on: https://gitea.tendokyu.moe/Hay1tsme/artemis/pulls/25

core/data/schema/versions/SDDT_4_rollback.sql

@@ -0,0 +1,2 @@
+ALTER TABLE ongeki_static_events
+DROP COLUMN startDate;

core/data/schema/versions/SDDT_5_upgrade.sql

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+ALTER TABLE ongeki_static_events
+ADD COLUMN startDate TIMESTAMP NOT NULL DEFAULT current_timestamp();