Add bundles for organizing bookmarks (#1097)

* add bundle model and query logic

* cleanup tests

* add basic form

* add success message

* Add form tests

* Add bundle list view

* fix edit view

* Add remove button

* Add basic preview logic

* Make pagination use absolute URLs

* Hide bookmark edits when rendering preview

* Render bookmark list in preview

* Reorder bundles

* Show bundles in bookmark view

* Make bookmark search respect selected bundle

* UI tweaks

* Fix bookmark scope

* Improve bundle preview

* Skip preview if form is submitted

* Show correct preview after invalid form submission

* Add option to hide bundles

* Merge new migrations

* Add tests for bundle menu

* Improve check for preview being removed

bookmarks/styles/theme/utilities.css

@@ -242,6 +242,14 @@
   margin-top: var(--unit-4) !important;
 }
 
+.ml-auto {
+  margin-left: auto;
+}
+
+.mr-auto {
+  margin-right: auto;
+}
+
 .mx-auto {
   margin-left: auto;
   margin-right: auto;