[LSST|dm-users 693] Default astrometry task changed

[Russell Owen]

As of this morning, on pipe_base master, the default astrometry task used by the calibration task is now the newer AstrometryTask (which we adpated from HSC) rather than the older ANetAstrometryTask (which uses the astrometry_net solver).

As a result some config override files may require changes. I searched all obs_* packages except obs_decam and only found the need for a few minor changes in obs_subaru. But you may have other files that require updating. Search for "calibrate.astrometry" to see items that might need updating. A few known cases:
- calibrate.astrometry.solver is now calibrate.astrometry.refObjLoader, and not all options are the same
- config.calibrate.astrometry.solver.calculateSip no longer exists, and there is no need to disable SIP fitting if WCS fitting is disabled using calibrate.astrometry.forceKnownWcs=True

The new astrometry task was already being used in two places:
- In obs_subaru for processCcd.py (but not processStack.py)
- By lsst_dm_stack_demo (which is used as the CI integration test)

Updated packages are pipe_tasks and obs_subaru. The ticket is DM-2792 <https://jira.lsstcorp.org/browse/DM-2792>

-- Russell