Expand data presented in interaction.guild

[VelvetToroyashi]

interaction.guild is a very sparsely documented object (read: "partial guild")

According to advaith, this currently includes id, features, and locale.

Exposing the guild's boost level would also be a useful metric to [explicitly] have here for some bots that upload content directly to Discord, as upload limits are tied to this metric, and requires fetching the guild over REST (or caching from gateway events), which may not always be possible or feasible.