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/_SpacePanel.scss

@@ -23,7 +23,7 @@ $activeBackgroundColor: $panel-actions;
 $activeBorderColor: $primary-content;
 
 .mx_SpacePanel {
-    background-color: $groupFilterPanel-bg-color;
+    background-color: $spacePanel-bg-color;
     flex: 0 0 auto;
     padding: 0;
     margin: 0;
@@ -309,13 +309,13 @@ $activeBorderColor: $primary-content;
         .mx_NotificationBadge_dot {
             // make the smaller dot occupy the same width for centering
             margin: 0 -1px 0 0;
-            border: 3px solid $groupFilterPanel-bg-color;
+            border: 3px solid $spacePanel-bg-color;
         }
 
         .mx_NotificationBadge_2char,
         .mx_NotificationBadge_3char {
             margin: -5px -5px 0 0;
-            border: 2px solid $groupFilterPanel-bg-color;
+            border: 2px solid $spacePanel-bg-color;
         }
     }