Delete groups (legacy communities system) (#8027)

* Remove deprecated feature_communities_v2_prototypes

* Update _components

* i18n

* delint

* Cut out a bit more dead code

* Carve into legacy components

* Carve into mostly the room list code

* Carve into instances of "groupId"

* Carve out more of what comes up with "groups"

* Carve out some settings

* ignore related groups state

* Remove instances of spacesEnabled

* Fix some obvious issues

* Remove now-unused css

* Fix variable naming for legacy components

* Update i18n

* Misc cleanup from manual review

* Update snapshot for changed flag

* Appease linters

* rethemedex

* Remove now-unused AddressPickerDialog

* Make ConfirmUserActionDialog's member a required prop

* Remove useless override from RightPanelStore

* Remove extraneous CSS

* Update i18n

* Demo: "Communities are now Spaces" landing page

* Restore linkify for group IDs

* Demo: Dialog on click for communities->spaces notice

* i18n for demos

* i18n post-merge

* Update copy

* Appease the linter

* Post-merge cleanup

* Re-add spaces_learn_more_url to the new SdkConfig place

* Round 1 of post-merge fixes

* i18n

Co-authored-by: Michael Telatynski <7t3chguy@gmail.com>

res/css/structures/_SpaceRoomView.scss

@@ -184,18 +184,6 @@ $SpaceRoomViewInnerWidth: 428px;
             }
         }
 
-        .mx_SpaceRoomView_preview_migratedCommunity {
-            margin-bottom: 16px;
-            padding: 8px 12px;
-            border-radius: 8px;
-            border: 1px solid $input-border-color;
-            width: max-content;
-
-            .mx_BaseAvatar {
-                margin-right: 4px;
-            }
-        }
-
         .mx_SpaceRoomView_preview_inviter {
             display: flex;
             align-items: center;