chore: Add more missing stuff

[advaith1]

#156 did not, actually, totally get up to date
hopefully, this does but no promises

• fix docs links to application object
• Guild Member Update member joined_at is nullable
• fix docs links to Update Presence
• move application object & flags to new file
• update embed desc limit to 4096
• update guild max_presence desc
• add team.name
• add application webhook type
• add missing json error codes (there were a lot)
• update channel name min char limit to 1
• document sending/editing components in messages
• embeds is nullable while editing
• add missing "see" links to edit msg
• add adding attachments while editing
• add removing attachments while editing
• add missing "see" links to execute webhook
• add application-owned webhook restriction for components
• add editing components in webhook messages
• add removing attachments in webhook messages
• moves execute webhook thread_id from json body to query