Refactor filter panels and enhance sidebar functionality

- Updated filter panel toggle icons from chevron-up to chevron-down across multiple pages for consistency.
- Added 'collapsed' class to filter content divs to manage visibility state.
- Enhanced library page button for tidying up media items, replacing the trash icon with a custom SVG broom icon.
- Improved CSS styles for sidebar and page header to ensure visibility and proper layout when the sidebar is collapsed.
- Introduced JavaScript functionality to manage sidebar width and state, including theme toggle for light/dark mode.
- Created a new notification drawer template that adapts based on the compact view state.

custom/otssignange/views/authed-notification-drawer.twig

@@ -0,0 +1,26 @@
+{#
+  Compact-aware notification drawer override
+#}
+{% if compact is defined and compact %}
+<div class="dropdown nav-item item ots-notif-compact">
+  <a href="#" class="nav-link" data-toggle="dropdown" id="navbarNotificationDrawer">
+    <span class="ots-topbar-icon fa fa-bell" aria-hidden="true"></span>
+  </a>
+  <div class="dropdown-menu dropdown-menu-right ots-notif-menu" aria-labelledby="navbarNotificationDrawer">
+    <div class="dropdown-header">Notifications</div>
+    <div class="dropdown-divider"></div>
+    <div class="dropdown-item">No new notifications</div>
+  </div>
+</div>
+{% else %}
+<li class="dropdown nav-item item">
+  <a href="#" class="nav-link" data-toggle="dropdown" id="navbarNotificationDrawer">
+    <span class="ots-topbar-icon fa fa-bell" aria-hidden="true"></span>
+  </a>
+  <div class="dropdown-menu dropdown-menu-right ots-notif-menu" aria-labelledby="navbarNotificationDrawer">
+    <div class="dropdown-header">Notifications</div>
+    <div class="dropdown-divider"></div>
+    <div class="dropdown-item">No new notifications</div>
+  </div>
+</li>
+{% endif %}