Fix edge cases with parser

- Remove front_matter dependency, and use a hand-rolled simpler parser
  which is suitable for the data to parse (which is well-formed).
- Fix a couple of edge cases with years and titles with commas

mix.exs

@@ -38,7 +38,7 @@ defmodule MusicLibrary.MixProject do
       {:ecto_sqlite3, ">= 0.0.0"},
       {:phoenix_html, "~> 4.1"},
       {:phoenix_live_reload, "~> 1.2", only: :dev},
-      {:front_matter, "~> 1.0"},
+      {:yaml_elixir, "~> 2.11"},
       # TODO bump on release to {:phoenix_live_view, "~> 1.0.0"},
       {:phoenix_live_view, "~> 1.0.0-rc.1", override: true},
       {:floki, ">= 0.30.0", only: :test},