Initial yt-dlp implementation (#3)

* Added basic runner for yt-dlp commands

* Updated formatting rules

* Added JSON runner; Added test script for CLI interactions

* Reworked yt-dlp runner; added proper test mocks

.formatter.exs

@@ -2,5 +2,6 @@
   import_deps: [:ecto, :ecto_sql, :phoenix],
   subdirectories: ["priv/*/migrations"],
   plugins: [Phoenix.LiveView.HTMLFormatter],
-  inputs: ["*.{heex,ex,exs}", "{config,lib,test}/**/*.{heex,ex,exs}", "priv/*/seeds.exs"]
+  inputs: ["*.{heex,ex,exs}", "{config,lib,test}/**/*.{heex,ex,exs}", "priv/*/seeds.exs"],
+  line_length: 100
 ]