Add missing bucket ids and RequestOptions in GetInteractionResponse()

Initial pass at making slash commands respond as expected

Fix content length check in CreateInteractionResponse()

Added SocketApplicationCommands, Added method in SocketGuild to fetch that guilds ApplicationCommands.

Tested all rest routes and fixed them accordingly.

Did more testing and I think its ready to go

New Rest entities: RestApplicationCommand,RestGlobalCommand, RestGuildCommand, RestApplicationCommandOption, RestApplicationCommandChoice, RestApplicationCommandType.

Added public methods to the RestClient to fetch/create/edit interactions.