In https://github.com/xwiki/xwiki-platform/blob/cace65ffccdac07d4a168d56cb5de6649701ed50/xwiki-platform-core/xwiki-platform-security/xwiki-platform-security-requiredrights/xwiki-platform-security-requiredrights-ui/src/main/resources/js/security/requiredrights/requiredRightsDialog.js#L75-L165 we already have a relatively comprehensive icon loader helper that could be made generally available. I'm sure it could be improved, but it actually already does more than what the code where it is used needs.
