Add pressure calibration functionality for coeffs and pre-deployment

[Klankers]

Current SBE9 processing does not apply the post-cal offset and slope coefficients, common as sensors age.
ODF calibrations default these values to 0.0 and 1.0, respectively. SeaBird and other institutions do not and they can be considerable in magnitude.

• Add the offset and slope coeffs to the sbe9 translation function when the sensor is originally translated to science units, whatever the new SBEReader looks like.

There are instances where the post-cast on-deck pressure is not available, so a linear slope adjustment cannot be applied. However, there are instances where the CTD is turned on before going in the water.

• Add a method for a single-point offset adjustment on the CTD pressure while on deck.