Switch to sqlite (#22)

* Updated project to use sqlite

* Edited migrations directly because I fear no man

* Updated search functions and tests to work with sqlite

* Updated build tools to remove postgres

priv/repo/migrations/20240130161316_add_media_item_to_tasks.exs

@@ -3,7 +3,7 @@ defmodule Pinchflat.Repo.Migrations.AddMediaItemToTasks do
 
   def change do
     alter table(:tasks) do
-      # `restrict` because we need to be sure to delete pending tasks when a channel is deleted
+      # `restrict` because we need to be sure to delete pending tasks when a media item is deleted
       add :media_item_id, references(:media_items, on_delete: :restrict), null: true
     end