Disable self-hosted Studio features via server environment variable

[mauzybwy]

Currently, to disable features in Studio, one must set the env var NEXT_PUBLIC_DISABLED_FEATURES. This variable is only used in the Next.js client, and overwrites the profile fetched from the api. A la apps/studio/data/profile/profile-query.ts:

if (!IS_PLATFORM) {
  return {
   ...data,
     disabled_features: process.env.NEXT_PUBLIC_DISABLED_FEATURES?.split(',') ?? [],
  } as Profile
} else {
  return data as Profile
}

The annoying side-effect of this is that the only way to change the disabled_features list when self-hosting is by modifying the Studio Dockerfile to add something like this:

ENV NEXT_PUBLIC_DISABLED_FEATURES="realtime:all"

As a potential solution to a simpler runtime configuration when self-hosting, @ivasilov suggested in this Discord thread that instead of overwriting the profile object on the client, it would be feasible to instead just return a profile object with the disabled_features field populated from the api by adding something like this to apps/studio/pages/api/platform/profile/index.ts:

if (!IS_PLATFORM) {
  response.disabled_features = process.env.DISABLED_FEATURES?.split(',') ?? []
}

[mauzybwy]

Created a draft PR here #41501