Currently the IdP provider logos in for the login theme are being constructed from a font-based spite-sheet. This is problematic, as it loads entire sprite sheets for presenting a couple of icons. Instead, an IdP should provide an icon file that can be loaded statically.

Under this issue the following needs to happen:

• Stop loading sprite sheets for font icons for the IdPs (such as the side-loaded PF4 icons, and various FontAwesome icon classes).
• Replace the aforementioned icons with proper SVG versions.
• Deprecate IdentityProviderBean#getLoginIconClasses(), and create an issue to remove this method in the next major.