Feature: #75579 - Add markupIdentifier support to JavaScript IconAPI

See Issue #75579

Description

It is now possible to request alternative rendering methods also through the JavaScript IconAPI for the backend. A new parameter has been added to the getIcon function that now accepts the markupIdentifier for alternative rendering output, as it's also possible within PHP.

Currently this is only used by the SvgIconProvider to deliver inline-SVGs instead of linking them in an img tag.

Example 1: default, without alternativeMarkup

require(['TYPO3/CMS/Backend/Icons'], function(Icons) {
   var iconName = 'actions-view-list-collapse';
   Icons.getIcon(iconName, Icons.sizes.small).done(function(icon) {
      console.log(icon);
   });
});

Example 2: with alternativeMarkup = inline

require(['TYPO3/CMS/Backend/Icons'], function(Icons) {
   var iconName = 'actions-view-list-collapse';
   Icons.getIcon(iconName, Icons.sizes.small, null, null, 'inline').done(function(icon) {
      console.log(icon);
   });
});