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

test/support/scripts/yt-dlp-mocks/repeater.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+if [[ "$@" == *"--dump-json"* ]]; then
+  echo '{ "args": "'$@'"}'
+else
+  echo $@
+fi