Add the ability to adjust thresholds and other tunables without recompiling.

[blu28]

Sometimes things change over the course of a competition. It might become necessary to adjust a PID set point, or threshold, or scaling factor to a new value and it would be great if doing so did not require making a code change and new deploy. Rick has also requested that things like the arm position set points be able to be nudged up or down from the controller, possibly using the DPAD.

As a general rule, we should put all tunables into the preferences class, or find a suitable way to configure them. They should be logged in the telemetry logs and on the console whenever they are changed, and it would be wise to put them under source code control if possible.