Add autonomous "move to position" command for the elevator

[SPCOxion]

[SPCOxion]

Implementing this command will be... interesting. I'd like to just make a command that just sets the target position of the elevator and finishes, which would probably work. However, if we use that in a command group, the next sequences might begin before the elevator has actually gotten where we want it to be, which would be Bad.

[SPCOxion]

Fix: Add a "Wait for Elevator" command. Basically it's like a wait command, but instead of just waiting for a certain time, it waits for the elevator to get to its' target position. Note that, the way it's currently implemented on the elevator branch, it has a timeout as well as a failsafe. We might want to change those timeout values if the elevator moves too slowly to get to its' target position in the default amount of time.