[Enhancement] Delete media after "x" days (#160)

* [Enhancement] Adds ability to stop media from re-downloading (#159)

* Added column

* Added methods for ignoring media items from future download

* Added new deletion options to controller and UI

* Added controller actions and UI for editing a media item

* Added column to sources

* Added retention period to form

* [WIP] getting retention methods in place

* Hooked up retention worker

* Added column and UI to prevent automatic deletion

* Docs

* Removed unused backfill worker

* Added edit links to media item tabs on source view

* Clarified form wording

* Form wording (again)

lib/pinchflat_web/controllers/sources/source_html/index.html.heex

@@ -22,6 +22,13 @@
         <:col :let={source} label="Should Download?">
           <.icon name={if source.download_media, do: "hero-check", else: "hero-x-mark"} />
         </:col>
+        <:col :let={source} label="Retention">
+          <%= if source.retention_period_days && source.retention_period_days > 0 do %>
+            <%= source.retention_period_days %> day(s)
+          <% else %>
+            <span class="text-lg">∞</span>
+          <% end %>
+        </:col>
         <:col :let={source} label="Media Profile">
           <.subtle_link href={~p"/media_profiles/#{source.media_profile_id}"}>
             <%= source.media_profile.name %>