FEATURE: modal for admins to edit Community section (#21668)

Allow admins to edit Community section. This includes drag and drop reorder, change names, delete and reset to default.

Visual improvements introduced in edit community section modal are available in edit custom section form as well. For example:
- drag and drop links to change their position;
- smaller icon picker.

config/locales/client.en.yml

@@ -4413,10 +4413,13 @@ en:
           save: "Save"
           delete: "Delete"
           delete_confirm: "Are you sure you want to delete this section?"
+          reset_confirm: "Are you sure you want to reset this section to default?"
           public: "Make this section public and visible to everyone"
+          more_menu: "More menu"
           links:
             add: "Add another link"
             delete: "Delete link"
+            reset: "Reset to default"
             icon:
               label: "Icon"
               validation:
@@ -4473,7 +4476,8 @@ en:
           configure_defaults: "Configure defaults"
         community:
           header_link_text: "Community"
-          header_action_title: "Create a topic"
+          header_action_create_topic_title: "Create a topic"
+          header_action_edit_section_title: "Edit Community section"
           links:
             about:
               content: "About"