[Alpha] 0.0.8

• Message#deleteMessage -> Message#delete
• Fix ModalSubmitInteraction referencing guild.id, which may not be present
• Add to, remove from & update channel threads collections on creation/deletetion/update
• add permissionsOf to ThreadChannel (returns the parent channel's permissions)
• specific interaction types for guild & dm
• [renamed type] AnyGatewayInteraction -> AnyInteractionGateway
• make ALL intents work properly
• Guild#joinedAt is optional
• Add threads collection to AnnouncementChannel
• Implement Forum channels