Update/fontawesome review

[marcelmoreau]

Made some changes which you can review:

• added one @use line in the entrypoint scss, linking to a vendor dir I made – I just feel this is cleaner
• within vendor/fontawesome file, I @import the assets. I banged my head wildly with @use and @forward. I can screenshare if you want to see the issue as I remember it. But, I don't know if we are worried about local/global scope stuff with FA anyway
• In addition to using mixins, we should be able to paste in markup from the FA site. We were not set up for this before. <i class="fas fa-check"></i>. I added one rule for this. We still don't have an area to showcase this on the frontend. Not sure where we document. I would expect a user to be able to have the ability to use FA html
• the fa($character: "", $set: fas) mixin did not work if you provided a number as the $set value. No font-family was declared. I was working on it, but I don't think we should let anyone put in a number here. These numbers may not stay the same in the future. I removed it.
• I included fa-icon in fa(). This will be DRYer in the output CSS.

[khamer]

This looks good - and it works here - https://deploy-preview-26--imarc-boilerplate.netlify.app/components/detail/messaging.html

I think the only reason I made the mixin different from .fas/.fab/etc. was so that you could use it on an element that contained other stuff (say, on an <li>) and only have those properties affect the pseudo element, whereas <li class="fas fa-check"> Task</li> wouldn't work the way we'd want generally, but maybe no one would do that anyway.

I think it would be worthwhile to make a small .twig to go with _fontawesome.scss to show that it's included and have it show up in the pattern library - it doesn't have to be anything special.