While working on DM-35939, I noticed some things in pipe_tasks/functors.py that should be cleaned up by someone who understands it (probably from DRP).

• NanoMaggie: I think we should just remove this one: the project isn't going to produce any values in nanomaggies.
• Mag/MagErr vs. Magnitude: I think we can safely just remove both of these, and `Photometry` and its subclasses. I think these are fully supplanted by the various `LocalPhotometry` classes.
  • Mag claims to take a `calib` object, which hasn't existed for years, and it calls calib.getFluxMag0 which hasn't existed on Calib's replacement PhotoCalib for years, either.
  • Magnitude (and Photometry and all it's subclasses) is undocumented, but also wants a `calib` object and calls `getFluxMag0`.
• ConvertPixelToArcseconds and ConvertPixelSqToArcsecondsSq: I think the docstrings on these are reversed, and should probably be made into proper english.
• SdssTraceSize: the docstring for this does not help me understand what an "sdss trace size" is.

The following have no docstrings:

• DeconvolvedMoments, HsmFwhm, E1, E2, RadiusFromQuadrupole, ReferenceBand, NumStarLabeller, StarGalaxyLabeller, Labeller, FootprintNPix, IDColumn