Use Font Awesome Kits to use the latest version of icons

Close #2184

update Font Awesome (#2150)

REF: https://fontawesome.com/changelog/latest

Merge branch 'master' of https://github.com/mmistakes/minimal-mistakes

* 'master' of https://github.com/mmistakes/minimal-mistakes:
  Allow adding JavaScript files after the theme's (#2116)

Allow adding JavaScript files after the theme's (#2116)

Allow adding JavaScript files after those bundled in the theme

Close #2110 

Merge branch 'master' of https://github.com/mmistakes/minimal-mistakes

Update Font Awesome (#2102)

REF: https://github.com/FortAwesome/Font-Awesome/blob/master/CHANGELOG.md

Replace jQuery Smooth Scroll with Smooth Scroll + Gumshoe (#2082)

* Replace jQuery Smooth Scroll with Smooth Scroll + Gumshoe
* Change smooth scrolling speed
* Set maximum smooth scroll duration
* Remove Font Awesome CSS Ppseudo elements attribute from JS script

Close #2050, close #2075

update Font Awesome (#2053)

* update Font Awesome

REF: https://fontawesome.com/changelog/latest

* Update _includes/scripts.html

Co-Authored-By: coliff <christianoliff@yahoo.com>

update font awesome (#1995)

REF: https://fontawesome.com/changelog/latest

Fix FontAwesome script

ref #1922

Add `crossorigin` attribute to FontAwesome script

ref #1922

add integrity hash for Font Awesome script (#1922)

* add integrity hash for Font Awesome script

As the script is loaded from an external CDN (use.fontawesome.com), its integrity must be ensured mainly for security reasons.
This hash must be updated together with the exact version of Font Awesome, as given on their website.

* Update to FontAwesome 5.5.0

Revert caching for comments and analytics. Fixes #1905 (#1907)

Cache "static" includes to improve build performance (#1874)

* Add jekyll-include-cache plugin
* Cache "static" includes to improve build performance
* Update CHANGELOG and history

"Static" refers to those includes that don't rely on data passed from the page content.

Update Font Awesome to latest version (#1830)

Merge branch 'master' of https://github.com/mmistakes/minimal-mistakes

Update font awesome (#1754)

* Update scripts.html

* update to 5.2.0

REF: https://github.com/FortAwesome/Font-Awesome/releases

update Font Awesome (#1711)

REF: https://github.com/FortAwesome/Font-Awesome/blob/master/CHANGELOG.md

Merge branch 'master' of https://github.com/mmistakes/minimal-mistakes

Implement feature #1652 google custom search support.  (#1667)

Implement feature #1652 google custom search support. For now we only support the look and feel "results only" and the engine must be set to use that layout. Add a google section to the search providers and search_form and search layout.

Close #1652