Add support for Font Awesome

[daveaglick]

Need to decide how this should fit in with Bootstrap icons. Should they be added to the Bootstrap icon enum in the base library (with a prefix perhaps). Or maybe an additional extension library with a separate enum and extra extensions for every method that takes an icon.

[srigaux]

I have just publish two nuget packages which can help you : https://www.nuget.org/packages/FluentFontAwesome/ https://www.nuget.org/packages/FluentFontAwesome.Mvc/