feat: add room list section labs flag

Author: florianduros

apps/web/src/i18n/strings/en_EN.json

@@ -1567,6 +1567,7 @@
         "render_reaction_images_description": "Sometimes referred to as \"custom emojis\".",
         "report_to_moderators": "Report to moderators",
         "report_to_moderators_description": "In rooms that support moderation, the “Report” button will let you report abuse to room moderators.",
+        "room_list_sections": "Room list sections",
         "share_history_on_invite": "Share encrypted history with new members",
         "share_history_on_invite_description": "When inviting a user to an encrypted room that has history visibility set to \"shared\", share encrypted history with that user, and accept encrypted history when you are invited to such a room.",
         "share_history_on_invite_warning": "This feature is EXPERIMENTAL and not all security precautions are implemented. Do not enable on production accounts.",

apps/web/src/settings/Settings.tsx

@@ -223,6 +223,7 @@ export interface Settings {
     "feature_dynamic_room_predecessors": IFeature;
     "feature_render_reaction_images": IFeature;
     "feature_new_room_list": IFeature;
+    "feature_room_list_sections": IFeature;
     "feature_ask_to_join": IFeature;
     "feature_notifications": IFeature;
     "feature_msc4362_encrypted_state_events": IFeature;
@@ -693,6 +694,15 @@ export const SETTINGS: Settings = {
         default: true,
         controller: new ReloadOnChangeController(),
     },
+    "feature_room_list_sections": {
+        supportedLevels: LEVELS_DEVICE_ONLY_SETTINGS_WITH_CONFIG_PRIORITISED,
+        labsGroup: LabGroup.Ui,
+        displayName: _td("labs|room_list_sections"),
+        description: _td("labs|under_active_development"),
+        isFeature: true,
+        default: false,
+        controller: new ReloadOnChangeController(),
+    },
     /**
      * With the transition to Compound we are moving to a base font size
      * of 16px. We're taking the opportunity to move away from the `baseFontSize`