Set VAL field from set point records for autosave

This merge request is part of the IonSrc IOC Review process.

The records included to autosave on this MR are:

ATU_tuner.template

$(P):$(R):PosXS
$(P):$(R):PosYS
$(P):$(R):SetupByte
$(P):$(R):GainS

Magnetron

$(P):$(R):ForwdPwrS
$(P):$(R):ReflPwrMaxS
$(P):$(R):SetupByte
$(P):$(R):StartModeS
$(P):$(R):StartTimS
$(P):$(R):StartTimSel
$(P):$(R):OvershootTimS
$(P):$(R):RampTimS
$(P):$(R):PulsLLvlS
$(P):$(R):PulsHLvlS
$(P):$(R):PulsFreqS
$(P):$(R):PulsWidthS