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/_RightPanel.scss

@@ -93,16 +93,6 @@ limitations under the License.
     mask-position: center;
 }
 
-.mx_RightPanel_groupMembersButton::before {
-    mask-image: url('$(res)/img/element-icons/community-members.svg');
-    mask-position: center;
-}
-
-.mx_RightPanel_roomsButton::before {
-    mask-image: url('$(res)/img/element-icons/community-rooms.svg');
-    mask-position: center;
-}
-
 $dot-size: 7px;
 $pulse-color: $alert;
 
@@ -234,7 +224,6 @@ $pulse-color: $alert;
 
 .mx_RightPanel .mx_MemberList,
 .mx_RightPanel .mx_MemberInfo,
-.mx_RightPanel .mx_GroupRoomList,
 .mx_RightPanel_blank {
     order: 2;
     flex: 1 1 0;