feat: add torznab feed support (#246)

* feat(torznab): initial impl

* feat: torznab processing

* feat: torznab more scheduling

* feat: feeds web

* feat(feeds): create on indexer create

* feat(feeds): update migration

* feat(feeds): restart on update

* feat(feeds): set cron schedule

* feat(feeds): use basic empty state

* chore: remove duplicate migrations

* feat: parse release size from torznab

* chore: cleanup unused code

internal/indexer/definitions/torznab_generic.yaml

@@ -0,0 +1,27 @@
+---
+#id: torznab
+name: Generic Torznab
+identifier: torznab
+description: Generic Torznab
+language: en-us
+urls:
+  - https://domain.com
+privacy: private
+protocol: torrent
+implementation: torznab
+supports:
+  - torznab
+source: torznab
+
+torznab:
+  minInterval: 15
+  settings:
+    - name: url
+      type: text
+      required: true
+      label: Torznab URL
+    - name: api_key
+      type: secret
+      required: false
+      label: Api key
+      help: Api key