Add icons to Konsole URL/mail context menu item

Summary:
URL: {F7821533}
Mail: {F7821534}

Test Plan: Open the context menu for an URL/mail address in Konsole.

Reviewers: #konsole, #vdg, ndavis, ngraham

Reviewed By: #vdg, ndavis, ngraham

Subscribers: ngraham, ndavis, #vdg, konsole-devel, #konsole

Tags: #konsole

Differential Revision: https://phabricator.kde.org/D26053