Implement basic soft logout handling

Fixes https://github.com/vector-im/riot-web/issues/10235

CSS and copy are left as an exercise for a later iteration.

Login page handling is left for https://github.com/vector-im/riot-web/issues/10236

This implementation reuses as much of the Lifecycle flow as it can without causing problems. Most importantly, it requires https://github.com/matrix-org/matrix-js-sdk/pull/975 to be able to detect a soft logout and react to it. When it comes time to starting/stopping the Lifecycle, additional parameters are provided so that the auxiliary services can (re)start themselves without the client starting to sync.

src/stores/CustomRoomTagStore.js

@@ -122,6 +122,7 @@ class CustomRoomTagStore extends EventEmitter {
                 }
             }
             break;
+            case 'on_client_not_viable':
             case 'on_logged_out': {
                 // we assume to always have a tags object in the state
                 this._state = {tags: {}};

src/stores/LifecycleStore.js

@@ -63,6 +63,7 @@ class LifecycleStore extends Store {
                 dis.dispatch(deferredAction);
                 break;
             }
+            case 'on_client_not_viable':
             case 'on_logged_out':
                 this.reset();
                 break;

src/stores/RoomListStore.js

@@ -261,6 +261,7 @@ class RoomListStore extends Store {
             //     console.log("!! Optimistic tag failure: ", payload);
             // }
             // break;
+            case 'on_client_not_viable':
             case 'on_logged_out': {
                 // Reset state without pushing an update to the view, which generally assumes that
                 // the matrix client isn't `null` and so causing a re-render will cause NPEs.

src/stores/RoomViewStore.js

@@ -103,6 +103,7 @@ class RoomViewStore extends Store {
             case 'join_room_error':
                 this._joinRoomError(payload);
                 break;
+            case 'on_client_not_viable':
             case 'on_logged_out':
                 this.reset();
                 break;

src/stores/SessionStore.js

@@ -68,6 +68,7 @@ class SessionStore extends Store {
                     cachedPassword: null,
                 });
                 break;
+            case 'on_client_not_viable':
             case 'on_logged_out':
                 this._setState({
                     cachedPassword: null,

src/stores/TagOrderStore.js

@@ -166,6 +166,7 @@ class TagOrderStore extends Store {
                 });
                 Analytics.trackEvent('FilterStore', 'deselect_tags');
             break;
+            case 'on_client_not_viable':
             case 'on_logged_out': {
                 // Reset state without pushing an update to the view, which generally assumes that
                 // the matrix client isn't `null` and so causing a re-render will cause NPEs.