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/_SpaceHierarchy.scss

@@ -258,7 +258,7 @@ limitations under the License.
         }
 
         &:hover, &:focus-within {
-            background-color: $groupFilterPanel-bg-color;
+            background-color: $spacePanel-bg-color;
 
             .mx_AccessibleButton {
                 visibility: visible;
@@ -280,7 +280,7 @@ limitations under the License.
         &::before {
             content: "";
             position: absolute;
-            background-color: $groupFilterPanel-bg-color;
+            background-color: $spacePanel-bg-color;
             width: 1px;
             height: 100%;
             left: 6px;