Upgrade icons to font awesome v6 - first steps

[robyngit]

MetacatUI currently uses icons from Font Awesome v3.2 from 2013, while the newest version from 2024 is version 6. See all versions here. In the last 10+ years, styles have been updated and new icons have been added. The much greater variety of icons in version 6 would be really helpful in improving the user interface of MetacatUI. It would also allow us to replace custom images and svgs that are inconsistent with the rest of the interface with icons that are part of this library.

This feature will help us in the design and implementation of the Cesium portal features that are under development for the PDG.

Since the icons are used throughout the MetacatUI interface, we may need to make updates in stages. This issue encompasses the first stage only, which involves importing the new fontawesome library and using it in the Cesium map interface. We can create additional issues for subsequent steps.

• Import fontawesome v6 and ensure no conflicts
• In the Cesium map: Update tool bar pills and layer category icons to use <i /> instead of <svg />
• [Nice-to-have] Update icons in the Cesium viewfinder and layers panels to use fontawesome v6