Changes:
1. Adding the `Fast` expressions where needed
2. Break the channel permissions into categories in PermissionsStore
3. Remove unused/unneeded code
Motivation:
ChannelsSelectionModel.qml is freezing the app when used with a live channel that's being edited because on each channel change the selection model is re-created.
The fix for this is to use the LeftJoinModel to unify the channels selection (a light model containing only keys) and the full channels model containing the channels data. On top of this, the SortFilterProxyModel is added to decorate the model with the roles expected in the UI. Another improvement is by replacing the ExpressionRole with the FastExpressionRole.
- Renamed main `CommunitiesPortal` folder to `Communities`.
- Created new `layouts` folder.
- Moved layout files from chat to communities.
- Created new `helpers` folder.
- Moved helpers files from chat to communities.
- Moved `controls/community` files from chat to communities `controls`.
- Moved `panels/communities` files from chat to communities `panels`.
- Moved `popups/community` files from chat to communities `popups`.
- Moved `views/community` files from chat to communities `views`.
- Moved `CommunityBanner` file from shared to `Communities/controls`. Only used in communities context.
- Moved `CommunitySettingsView` and `CommunityColumnView` files from chat to communities `views`.
- Moved `PermissionsStore.qml` file to `shared/stores`.
- Updated imports.
- Updated storybook.
Part of #6204
Khushboo Mehta
Alex Jbanca
Noelia