New server-side deprecations system (replacing superseding)

[HJfod]

Introduces a new server-side system for deprecating mods (this used to be the "superseded" incompatibility level in mod.json)

Additions & changes

• Adds new endpoint /v1/mods/{id}/deprecate for checking and updating a mod's deprecation status
• /v1/mods/updates now returns an object containing updates as well as a list of deprecations for the given mods

Things that have to be done elsewhere:

• The Geode SDK client will then have to be updated to handle this new format and show the deprecations in the UI
• The Geode SDK website needs to be updated to add an UI for developers & admins to create deprecations

[Fleeym]

Basically only small nitpicks, I can fix them up after I merge the PR, lemme know if you wanna fix them.

[Fleeym]

Did some stuff myself, should be good to go now.

[Fleeym]

Actually scratch that I forgot to add updated_by tracing