Add the ability for a customizer control to render its controls via a JavaScript template. Switches the default color picker control to a JavaScript template. See #29572. Props celloexpressions

git-svn-id: https://develop.svn.wordpress.org/trunk@30014 602fd350-edb4-49c9-b593-d223f7449a82

Conflicts:
	src/wp-admin/js/customize-controls.js
	src/wp-includes/class-wp-customize-control.php