Add support for StackOverflow icon

[dhouck]

Subject of the feature

There should be an icon for Stack Overflow profiles, like other profile types

Problem

The resume looks weird without an icon there and it is not obvious there is a link to click; on paper it is only slightly better.

Expected behaviour

When I put a profile with a network of stackoverflow or stack-overflow, there should be an icon, like here:

But instead there is a blank space:

Further details

I am confused about how this project is set up, probably because I am not a web developer at all. It looks like the icons are in the lib/resume.hbs file, but thereʼs also a list of icons in raw/eloquent-icomoon.json, which does include StackOverflow. If only the first file is relevant, then adding the

<symbol id="icon-stackoverflow" viewBox="0 0 25 30"><path d="M21 27v-8h3v11H0V19h3v8h18Z" fill="#BCBBBB"></path><path d="M17.1.2 15 1.8l7.9 10.6 2.1-1.6L17.1.2Zm3.7 14.7L10.6 6.4l1.7-2 10.2 8.5-1.7 2ZM7.2 12.3l12 5.6 1.1-2.4-12-5.6-1.1 2.4Zm-1.8 6.8 13.56 1.96.17-2.38-13.26-2.55-.47 2.97ZM19 25H5v-3h14v3Z" fill="#F48024"></path></symbol>

should solve it (thatʼs how I got the first screenshot). Iʼm only not submitting a PR because Iʼm not confident that is correct, given the other icon file.