Modify satbias converter to follow new file convention

[CoryMartin-NOAA]

Description

In order to generalize the satbias and satbias_cov I/O in UFO, we need to refactor the format of the satbias netCDF/IODA files. This issue will track the updates to the existing GSI to satbias converter, as well as a python script that will 'translate' between the old and new format for people to not lose work in the process when things are being updated.

Requirements

Coordinated with UFO for the aircraft VarBC code sprint as well as work in #804

Acceptance Criteria (Definition of Done)

This should be a coordinated merge with UFO

Dependencies

See above, #804 as well as https://github.com/JCSDA-internal/ufo/issues/2993

[BenjaminRuston]

this can be closed correct @huishao-r