BICAS: L2: Use NSO to set fill values for arbitrary antenna channel(s) (1x single+2x diffs) (when antenna does not work)

[ErikPGJ]

Problem

BICAS needs to handle ANT3 or other antennas breaking down, possibly intermittently, in a good way. This affects the generation of L3 too via solo.vdccal and solo.psp2ne().

NOTE:

• solo.vdccal() currently (2024-06-05) uses a constant TIME_PSP_BEGIN_SINGLE_PROBE = EpochTT('2022-12-15T00:00:00.000000000Z'); to specify when it shall begin assuming always single probe. (It can vary depending on data before the timestamp.)
• solo.psp2ne currently (2024-06-05) does not have any special handling of failing ANT3 but also does not yet cover the time when ANT3 fails (calibration data ends at 2022-12-31T23:59:59Z).

Solution to be implemented

It was agreed on IRFU RPW/BIAS calibration meeting 2024-06-04 to implement functionality for setting any selected L2 single antenna channel (1x single + 2x diffs) to fill values when the corresponding antenna-specific (to-be-defined) NSOID applies.

Fill values in channels should already be automatically be represented as NaN in the input data to solo.psp2ne() and solo.vdccal(). Those functions should thus be able to detect and handle the absence of data on arbitrary channels as they (should) already do, more or less (to be checked). They should thus do not need to be aware of failing antennas and be independent of the functionality for special handling of failing antennas (no change of interface).

TODO-NI: Do solo.psp2ne() and `solo.vdccal() handle NaN sufficiently well?
TODO: Define NSOIDs.
TODO-NI: Cap QUALITY_FLAG?

[ErikPGJ]

Should wait to implement this until #143 is completed since resolving #143 (a) refactors relevant code and (b) should make the implementation easier.