Viewport collections visibility popover

This brings the functionality currently in the H shortcut, to hide/show
individual collections.

In order to convey hierarchy, and to make justice to the originally
intended 1-10 shortcuts, we group the collections per siblings.

release/scripts/startup/bl_ui/space_view3d.py

@@ -245,6 +245,13 @@ class VIEW3D_HT_header(Header):
 
         layout.separator_spacer()
 
+        # Collection Visibility
+        layout.popover(
+            panel="VIEW3D_PT_collections",
+            icon='GROUP',
+            text="",
+        )
+
         # Viewport Settings
         layout.popover(
             panel="VIEW3D_PT_object_type_visibility",
@@ -4000,6 +4007,57 @@ class VIEW3D_PT_view3d_cursor(Panel):
         layout.column().prop(view, "cursor_location", text="Location")
 
 
+class VIEW3D_PT_collections(Panel):
+    bl_space_type = 'VIEW_3D'
+    bl_region_type = 'HEADER'
+    bl_label = "Collections Visibility"
+    bl_ui_units_x = 7
+
+    def _draw_collection(self, layout, view_layer, collection, index):
+        need_separator = index
+        for child in collection.children:
+            index += 1
+
+            if child.exclude:
+                continue
+
+            if child.collection.hide_viewport:
+                continue
+
+            if need_separator:
+                layout.separator()
+                need_separator = False
+
+            icon = 'BLANK1'
+            if child.has_selected_objects(view_layer):
+                icon = 'LAYER_ACTIVE'
+            elif child.has_objects():
+                icon = 'LAYER_USED'
+
+            row = layout.row()
+            row.alignment = 'LEFT'
+            row.active = child.has_visible_objects(view_layer)
+            row.operator("object.hide_collection", text=child.name, icon=icon, emboss=False).collection_index = index
+
+        for child in collection.children:
+            index = self._draw_collection(layout, view_layer, child, index)
+
+        return index
+
+    def draw(self, context):
+        layout = self.layout
+        layout.use_property_split = True
+
+        layout.label(text="Collections Visibility", icon='GROUP')
+        col = layout.column()
+
+        view_layer = context.view_layer
+        # We pass index 0 here beause the index is increased
+        # so the first real index is 1
+        # And we start with index as 1 because we skip the master collection
+        self._draw_collection(layout, view_layer, view_layer.layer_collection, 0)
+
+
 class VIEW3D_PT_object_type_visibility(Panel):
     bl_space_type = 'VIEW_3D'
     bl_region_type = 'HEADER'
@@ -5362,6 +5420,7 @@ classes = (
     VIEW3D_PT_view3d_properties,
     VIEW3D_PT_view3d_camera_lock,
     VIEW3D_PT_view3d_cursor,
+    VIEW3D_PT_collections,
     VIEW3D_PT_object_type_visibility,
     VIEW3D_PT_grease_pencil,
     VIEW3D_PT_gpencil_multi_frame,