Move invites to dedicated sections and enable section collapse (#5683)

* Display invites in dedicated sections

* Activate shrinkable and fix home number of rows for section

* Rework section header

* Display badge in people and room tabs

* Add changelog & remove useless todo

* Improve isSectionShrinked condition, remove useless import and shrinkable sets

* Restore invitation count in tab bar badge

* Display badge for invites section

* Add comment on invites count

* Update right accessory view on data source update

Co-authored-by: Arnaud Ringenbach <arnaud.ringenbach@niji.fr>

Riot/Modules/Rooms/RoomsViewController.m

@@ -72,7 +72,6 @@
     {
         // Take the lead on the shared data source.
         recentsDataSource = (RecentsDataSource*)self.dataSource;
-        recentsDataSource.areSectionsShrinkable = NO;
         [recentsDataSource setDelegate:self andRecentsDataSourceMode:RecentsDataSourceModeRooms];
     }
 }
@@ -102,17 +101,6 @@
 
 #pragma mark - UITableView delegate
 
-- (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
-{
-    if ([tableView numberOfSections] <= 1)
-    {
-        // Hide the header to merge Invites and Rooms into a single list.
-        return 0.0;
-    }
-    
-    return [super tableView:tableView heightForHeaderInSection:section];
-}
-
 - (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
 {
     if ([super respondsToSelector:@selector(tableView:willDisplayCell:forRowAtIndexPath:)])