Game collections

[chyyran]

Expose collections as isomorphic to the following GraphQL API

extend type Query {
    collections(where: CollectionsFilter) : Collection {
      collectionId: Uuid!
      collectionName: String!
    }
}

extend type Mutation {
   createCollection(collectionName: String!): Collection
   deleteCollection(collectionName: String!): Collection
}

Games can be added to a collection conventionally by setting a metadata value collection_in_{collectionId} to true.

Since this is exclusively a UI-only feature, we might want to keep this client-local, or alternatively, as an optional plugin that does not affect the main database.