Remove Sentry

Not used, and it has a quite a few outdated dependencies.

lib/music_library/application.ex

@@ -7,10 +7,6 @@ defmodule MusicLibrary.Application do
 
   @impl true
   def start(_type, _args) do
-    :logger.add_handler(:my_sentry_handler, Sentry.LoggerHandler, %{
-      config: %{metadata: [:file, :line]}
-    })
-
     children = [
       MusicLibraryWeb.Telemetry,
       MusicLibrary.Repo,