SVG / PNG icons

The new design requires group icons to have a different color in the homepage and internal pages.

Possible solutions:

1. Find some color that'll work with both (likely require changing the homepage design)

2. Have two sets of PNG icons, one for each color

3. Use SVG icons so we change color via the CSS, eg a class for each case

Seems like 3 is the best option as it will offer us more versatility and will be easier to use when site maintainers add new icons. @OriHoch please take a look and see how much work is needed to implement.

(GH doesn't allow attaching SVG to an issue. For testing you can get svg/png files of our Religion icon [here](https://www.flaticon.com/free-icon/pray_1644498?term=religion&page=1&position=17&related_item_id=1644498))

Start by locating how group icons are rendered on the homepage and internal pages, then inspect the related CSS and icon assets. Compare the three proposed approaches in the issue and confirm the chosen direction with maintainers. Done means group icons visibly use distinct colors in both contexts and newly added icons remain usable.

Written by the indexing model from the issue text.