To photograph a glass covered picture, you need two lights from each side at about 45 degree angles. The lights do not and should not be too close to the subject. In this way there will be uniform exposure over the artwork. A shooting enclosure would be a nightmare.
The lens of your camera needs to be parallel to the artwork. Unless you have a camera that has a lens shift function, like a view camera, your camera will reflect off the glass. Therefore, it is best to use a telephoto or slightly telephoto lens & cut a hole in black artboard or black felt like material, so just the lens pokes through, to minimize any camera reflection and block any light or reflective material from appearing in the glass, as it will act like a mirror. A simple lighting kit like the First Studio Portrait Kit DP-FSPTKT would be fine, and you would not need to use the umbrellas for this application, just the light heads. Then at another time, you could use the umbrellas for a portrait or similar. Or you could get the kit with the shooting enclosure First Studio Product Kit DP-FSPDKT, which you could use for other types of products. You will also need a tripod for the long exposures and be sure you white balance your camera.