minor #1077 [Site] New Icon component + assets optimisation (smnandre)

This PR was squashed before being merged into the 2.x branch.

Discussion
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[Site] New Icon component + assets optimisation

* new Icon twig component to handle SVG icons (and remove all FontAwesome scripts + fonts)
* clean & compress favicons
* expand header full-width on big screens
* clean footer
* fix layout + add UI effects on component list
* fix some minor misalignments

Commits
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a2b5d3b [Site] New Icon component + assets optimisation

Author: weaverryan