CoDICE: l3b_lo-3d-vdfs: add support variables

[mstarkey2158]

To better interpret the 3d VDF data, the CoDICE team would like to add the following varialbes:

• rgfo_esa_step
• rgfo_spin_sector
• rgfo_half_spin
• half_spin_per_esa_step

These will enable the user to know exactly when RGFO mode is active in the data to better evaluate science results.

[jtniehof]

These are basically carry-through from the inputs, correct?

[mstarkey2158]

@jtniehof correct, these would carry through from the l1a products. I think the priority counts has these, so you could carry them through from there.