Add improved admin camera

Shift + > (moves to next player on list)
Shift + < (moves to prev player on list)
Ctrl + E (exit the camera mode)
Control + / (Attaches to target, or detaches from target)
Control + H (toggle target HUD)
N  (cycles through NV, Thermal, and normal camera modes)
W,A,S,D (Move the camera in specified direction)
Q (Move the camera up, like helicopter)
Z (Move the camera down, like helicopter)
Mouse Move (Rotate camera naturally)
Scroll Wheel Up (Increase camera moving speed by 0.1 m/s, max 1 m/s)
Scroll Wheel Down (Decrease camera moving speed 0.1 m/s, min 0 m/s)
Shift + W,A,S,D (Move the camera, but faster, extra 3 m/s)