Remove ErrorTracker

Doesn't work with recent LiveView releases, and seems to be maintained
very slowly despite incoming PRs to fix the issues.

priv/repo/migrations/20250101170610_add_error_tracker.exs

@@ -1,11 +0,0 @@
-defmodule MusicLibrary.Repo.Migrations.AddErrorTracker do
-  use Ecto.Migration
-  def up, do: ErrorTracker.Migration.up(version: 4)
-
-  def down do
-    # Not sure why, but the built-in migration fails, so we're removing things manually
-    drop table(:error_tracker_meta)
-    drop table(:error_tracker_errors)
-    drop table(:error_tracker_occurrences)
-  end
-end

priv/repo/migrations/20250123104921_remove_error_tracker.exs

@@ -1,9 +0,0 @@
-defmodule MusicLibrary.Repo.Migrations.RemoveErrorTracker do
-  use Ecto.Migration
-
-  def change do
-    drop table(:error_tracker_meta)
-    drop table(:error_tracker_errors)
-    drop table(:error_tracker_occurrences)
-  end
-end