Revert "Implemented WMS legend images in layer detail window #251"

This reverts commit c4f5bcbda805a8805f8b05823946e6890f08f71d.
Revert "Revert "Implemented WMS legend images in layer detail window #251""

This reverts commit 3a7059c3bd863a175f232caad8cc89df72193b34.