* add `AppliedTags` property

* convert collections into immutable arrays

* remove "not supported" remark

* implement `ThreadChannelProperties`

* Add `DefaultSlowModeInterval` and `DefaultSlowModeInterval` properties to forum channels

* add `Moderated` property to `ForumTag``

* `ForumTag` inherits `ISnowflakeEntity`

* Fix `DiscordRestClient.GetChannelAsync` not getting forum channel

* a lot of changes

added:
- channel flags
- `ForumTagBuilder`
- imroved channel modification

* fixed a bug in forum tag emoji parsing

* inherit forum channel from `INesteeChannel`

* implement `INestedChannel` in forum channels

* Add `Flags` property to channels

* add iteraface for forum tags & add equality operators

* Add default reaction emoji property

* add support for modifing default reaction & some renaming

* add createForumChannelAsync to guild

* *fix resharper being a d... and moving code to next line*

* add a `ForumChannels` property

* Some fixes & add support for `default_sort_order`

* fix misleading comment

* fix #2502

* support creating post with applied tags

* fix xmldoc

* set category id on model update

* add limit checks for tag count

* initial implementation

* Update SocketForumChannel.cs

* rest forum channel and remove message builder for 4.x

* Update src/Discord.Net.Core/DiscordConfig.cs

Co-authored-by: Jared L <48422312+lhjt@users.noreply.github.com>

* Update src/Discord.Net.Core/Entities/Channels/IForumChannel.cs

Co-authored-by: Jared L <48422312+lhjt@users.noreply.github.com>

* Update src/Discord.Net.Core/DiscordConfig.cs

Co-authored-by: Jared L <48422312+lhjt@users.noreply.github.com>

* Update src/Discord.Net.Core/Entities/Channels/IForumChannel.cs

Co-authored-by: Jared L <48422312+lhjt@users.noreply.github.com>

* Update src/Discord.Net.Core/Entities/Channels/IForumChannel.cs

Co-authored-by: Jared L <48422312+lhjt@users.noreply.github.com>

* Update src/Discord.Net.Core/Entities/Channels/IForumChannel.cs

Co-authored-by: Jared L <48422312+lhjt@users.noreply.github.com>

Co-authored-by: Jared L <48422312+lhjt@users.noreply.github.com>