Update and clean-up

[gdude2002]

I haven't tested this (and don't currently have a setup to), so test it yourselves before merging!

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General Changes

• Replaced the unmaintained and buggy CadixDev Gradle licenser plugin with Yumi Gradle Licenser
• Updated the build scripts to use the new KordEx Gradle plugin
  • Removed dependencies, repositories and configurations automatically provided by the KordEx Gradle plugin
• Updated to Kotlin 2.0.20-Beta1 and KordEx 1.9.0-SNAPSHOT
• Updated Detekt and other dependencies

Extensions

• Removed
  • PK: the flag/moderation log wasn't that useful and the association is too close to PII
  • Suggestions: hasn't been used since Discord forum channels became a thing
  • Teams: was never really useful and never worked properly
  • User Clean-up: was only used for a short time and was counter-productive in the end
• Updated
  • Filtering: removed the storage of filter events as we only added them for Metabase and that's no longer used

Migrations

• Updated to no longer migrate data relevant to the above removed extensions
• Migration 25 added, which drops the data relevant to the above removals, as well as the collection previously used by the Server Applications extension (which has been gone for some time now)

[Southpaw1496]

Seems to be working in my testing.