Change Channel to Source (#12)

* Ensure channel detail lookup doesn't download the video - oops

* Ran the needful migrations for replacing channels with sources

* got media source test back working

* channel tasks test

* Media indexing worker test

* media tests

* Got all tests working except controller tests

* got all tests working

* Renamed Channel struct to Source

* renamed ChannelTasks

* More renaming; renamed channel details module

* Removed Channel yt-dlp module, instead throwing things in the VideoCollection module

* Renamed what looks like the last of the outstanding data

lib/pinchflat_web/controllers/media_sources/source_html/show.html.heex

@@ -0,0 +1,17 @@
+<.header>
+  Source <%= @source.id %>
+  <:subtitle>This is a source record from your database.</:subtitle>
+  <:actions>
+    <.link href={~p"/media_sources/sources/#{@source}/edit"}>
+      <.button>Edit source</.button>
+    </.link>
+  </:actions>
+</.header>
+
+<.list>
+  <:item title="Source Name"><%= @source.name %></:item>
+  <:item title="Source ID"><%= @source.collection_id %></:item>
+  <:item title="Original URL"><%= @source.original_url %></:item>
+</.list>
+
+<.back navigate={~p"/media_sources/sources"}>Back to sources</.back>