Release 7.4.2: Added update task to get aligned to a DB scheme after a fresh v7.4.1 installation

[Guest]

DB schemes differ if they are either freshly installed on a v7.4.1 basis or evolved through several release upgrades.

Therefore an update task is introduced that performs the necessary changes to get aligned to a fresh DB schema.

Associated update task name:
com.openexchange.groupware.update.tasks.DropFKTask v2