Add bookmark sharing (#311)

* Allow marking bookmarks as shared

* Add basic share view

* Ensure tag names in tag cloud are unique

* Filter shared bookmarks by user

* Add link for filtering by user

* Prevent n+1 queries when rendering bookmark list

* Prevent empty query params in return URL

* Fix user select template tag name

* Create shared bookmarks through API

* List shared bookmarks through API

* Show bookmark suggestions for shared view

* Show unique tags in search suggestions

* Sort user options

* Add bookmark sharing feature flag

* Add test for share setting default

* Simplify settings view

bookmarks/migrations/0017_userprofile_enable_sharing.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.2.14 on 2022-08-04 09:08
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('bookmarks', '0016_bookmark_shared'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='userprofile',
+            name='enable_sharing',
+            field=models.BooleanField(default=False),
+        ),
+    ]