Social Icons Widget: Add freeCodeCamp

[ipokkel]

• I have searched for similar features requests in both open and closed tickets and cannot find a duplicate.
• The feature is still missing in the latest stable version of Elementor ( Elementor Pro. )

What problem is your feature request going to solve? Please describe.
I'd like to be able to add freeCodeCamp as on of the social icons but it's not currently possible.

Describe the solution you'd like
The ability to add freeCodeCamp as a social icon in the Social Icons Widget. The icon is available in the fontawesome 4.7 as fa-free-code-camp.

Describe alternatives you've considered
Using the elementor icon list widget and applying styles

Additional context
Albeit this not being a crucial feature request as using the Icon List Widget is a viable alternative solution it would be much easier and faster if this could be possible through the social icons widget.

[ipokkel]

Added this, and others, see pull request #5820