* Introduces IconsHelper with methods to render SVG icon from a sprite file.
* Adds SVG sprite file with icons mainly from Font Awesome, but also from Material Design Icons and Fluent UI System Icons (based on the work made by Takashi Kato (@tohosaku)).
* Replaces specific icons with new SVG icons.
* Temporarily keep all old CSS icon definitions for backard compatibility.
git-svn-id: https://svn.redmine.org/redmine/trunk@22988 e93f8b46-1217-0410-a6f0-8f06a7374b81
includes a confirmation page that also gives the opportunity to lock
users instead of deleting them.
Patch by Jens Krämer.
git-svn-id: https://svn.redmine.org/redmine/trunk@21824 e93f8b46-1217-0410-a6f0-8f06a7374b81
