Add command target to MessageInteractionMetadata

[Soheab]

Summary

This PR adds support for the following new fields on MessageInteractionMetdata: target_user, target_message_id.

I have also split up the types like the API Docs.

Relevant links:

• Add command target to interaction response messages discord/discord-api-docs#7181
• https://discord.com/developers/docs/resources/message#message-interaction-metadata-object

Checklist

• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
• This PR fixes an issue.
• This PR adds something new (e.g. new method or parameters).
• This PR is a breaking change (e.g. methods or parameters removed/renamed)
• This PR is not a code change (e.g. documentation, README, ...)