Forum channel creation + forum post applied tags support

[tal5]

Additions

• DiscordScriptEvent#tryForumTag - for forum tag switches.
• discordcreatechannel command - forum channel creation support.
• discord forum post tags updated event - Triggers when a Discord forum post's tags change.
• DiscordChannelTag.applied_tags tag + mech - Controls a forum post's applied tags.
• DiscordChannelTag#getListForForumTags and DiscordChannelTag#getMapForForumTag - util methods for formatting forum tags into their MapTag format.

Changes

• discordcreatechannel command - forum channel creation support.
• Updates to JDA 5.0.0-alpha.21

Notes

• I added the util methods for converting forum tags into MapTags in DiscordChannelTag as that felt like a logical place and dDiscordBot doesn't have any Utilities class as far as I could see, let me know if these should be moved.
• The meta docs for switches in the new event are slightly different then other events as I tried including the fact that you can match by name as well (other events seem to only document matching by ID), let me know if that should be changed to match other events / to something else.

[tal5]

Currently a draft as it's waiting on a few bug fixes from JDA (I.e. the next JDA release), the PR itself should be ready for review