LPS-40876 - Convert minimized ctrl panel sidebar icons to using FontAwesome

https://issues.liferay.com/browse/LPS-40876

Hey Nate,

I added iconClass to the liferay-ui:panel taglib. I removed the css related to the old icons and adjusted the padding in .panels-minimized .panel-page-menu to center the new icons. In control_panel_menu/view.jsp, I added some logic to print the right icon name.

Patrick