`sar_sensitivity <cm/360>`

[ThisAMJ]

Create a command that calculates and sets your sensitivity from the provided units (I suggest cm/360 but there could be others people like, maybe support multiple). Suggested by @0atsy like a week ago, and it shouldn't be forgotten.

Also sar_sensitivity_get <units> to convert your current sensitivity to the aforementioned units, perchance.
AFAIK, mouse sensitivity in Portal 2 depends on DPI, sensitivity, screen resolution, and fov. The latter three we can fetch automagically, but DPI I'm not sure. We may need to provide it in the command.

[ThisAMJ]

1/m_yaw=sens/deg/dot (1 dot at 1/m_yaw sens = 1 degree)
thus (probably)
360/(m_yaw * dpi * sensitivity) = in/360
914.4/(m_yaw * dpi * sensitivity) = cm/360
dpi * sensitivity = eDPI
do we care about m_rawinput 0 users?