How to Raise and Lower an Object via Arduino/Photon
Several ways to do this.


Pulley and rope system that moves the light up or down. Requires a motor that can run in both directions and a set of small relays that you can control from your micro-controller.
As you said, linear actuators, though they have a limited scope of movement.
Threaded rod with a holder and a slot, similar to CNC machines but in an orientation you want. A motor rotates the rod and consequently the light is moved along the rod.