Deprecation warnings from afwGeom

Last year we announced that some functionality in the afw.geom package was being relocated to geom. When version 18 was released we announced that the aliases forwarding afw to geom will be removed following the release of version 19. To aid in that migration I have added formal deprecations to those routines so if you use them you will see a warning message indicating you should be using geom instead. The warning will look something like:

 FutureWarning: Call to deprecated function (or staticmethod) Point3D. (Replaced by lsst.geom.Point3D (will be removed before the release of v20.0))

There are some complications with associating deprecation warnings with constants so for now afwGeom.arcseconds and related items will not issue warnings. Please don’t use them any more.

To make things easier for people I have removed almost all usage of the relevant afwGeom routines from the Science Pipelines code. If I’ve missed any please fix them up when you see them to ensure that we have an easy migration when we do remove the aliases.