[WIP] Add support for new channel types.

Created by: WamWooWam

Summary

Adds "support" for news/store channels, closes #433 (closed)

Details

Discord somewhat recently added 2 new channel types, News and Store. News is literally just a text channel with a different icon (and I've treated it as such here), and store is magic discord commerce bullshit we dare not touch with a 10 foot pole.

Changes proposed

• Add News/Store to the ChannelType enum
• Change all checks for ChannelType.Text to also accept ChannelType.News

Notes

These changes are mostly locked behind sever verification/discord partnership, so I can't test this. As such I've marked this as a WIP PR until someone can.