New feature: str and repr for afw tables

I’ve just merged DM-6718, which gives usefully formatted stringification for afw tables and catalogs, and also lets them “automagically” be pretty-printed as html in jupyter notebook. See the image below for an example. Thanks to @kfindeisen for pair coding it with me, and @ctslater and @natelust for review comments.

This functionality should be available in the next weekly.

We never quite converged on recommendations for str and repr in LSST (e.g. this discussion), so I’ve handed all the hard work off to AstroPy, who have already put a lot of thought into this.