[Feature] Selects v2 support (#2507)

* Initial support for new select types

* Merge branch 'dev' of https://github.com/discord-net/Discord.Net into dev

* some component&action row builder additions

* remove redundant code

* changes1

* maybe working rest part?

* working-ish state?

* fix some xml docs & small rework

* typos

* fix `ActionRowBuilder`

* update DefaultArrayComponentConverter to accomodate new select-v2 types

* now supports dm channels in channel selects

* add a note to IF docs

* add notes about nullable properties

* <see langword="null"/>

* update Modal.cs

Co-authored-by: cat <lumitydev@gmail.com>
Co-authored-by: Cenngo <cenk.ergen1@gmail.com>

src/Discord.Net.Rest/Net/Converters/MessageComponentConverter.cs

@@ -30,6 +30,10 @@ namespace Discord.Net.Converters
                     messageComponent = new API.ButtonComponent();
                     break;
                 case ComponentType.SelectMenu:
+                case ComponentType.ChannelSelect:
+                case ComponentType.MentionableSelect:
+                case ComponentType.RoleSelect:
+                case ComponentType.UserSelect:
                     messageComponent = new API.SelectMenuComponent();
                     break;
                 case ComponentType.TextInput: