Channel types as classes

[valzargaming]

This pull request introduces new channel type classes to better represent the different types of Discord channels in the codebase, and updates the ChannelBuilder to map channel type integers to these new classes. This improves type safety, extensibility, and clarity when working with various channel types.

Channel Type Class Additions:

• Added new classes for each Discord channel type, including DM, GroupDM, GuildText, GuildVoice, GuildCategory, GuildAnnouncement, AnnouncementThread, PublicThread, PrivateThread, GuildStageVoice, GuildDirectory, GuildForum, and GuildMedia, all extending either Channel or Thread as appropriate. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13]

ChannelBuilder Enhancements:

• Updated ChannelBuilder to import all new channel type classes.
• Added a TYPES constant in ChannelBuilder that maps channel type integers to their corresponding class, providing a clear and maintainable way to handle channel instantiation by type.