Archive snapshots of websites locally (#672)

* Add basic HTML snapshots

* Implement asset list

* Add snapshot creation tests

* Add deletion tests

* Show file size

* Remove snapshots

* Create new snapshots

* Switch to single-file

* CSS tweak

* Remove auto refresh

* Show delete link when there is no file yet

* Add current date to display name

* Add flag for snapshot support

* Add option for disabling automatic snapshots

* Make snapshots sharable

* Document image variants

* Update README.md

* Add migrations

* Fix tests

bookmarks/migrations/0030_bookmarkasset.py

@@ -0,0 +1,43 @@
+# Generated by Django 5.0.2 on 2024-03-31 08:21
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("bookmarks", "0029_bookmark_list_actions_toast"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="BookmarkAsset",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                ("date_created", models.DateTimeField(auto_now_add=True)),
+                ("file", models.CharField(blank=True, max_length=2048)),
+                ("file_size", models.IntegerField(null=True)),
+                ("asset_type", models.CharField(max_length=64)),
+                ("content_type", models.CharField(max_length=128)),
+                ("display_name", models.CharField(blank=True, max_length=2048)),
+                ("status", models.CharField(max_length=64)),
+                ("gzip", models.BooleanField(default=False)),
+                (
+                    "bookmark",
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        to="bookmarks.bookmark",
+                    ),
+                ),
+            ],
+        ),
+    ]