What do we want to do with this ticket?

I suppose the bigger question is whether these examples will be mantained/updated to gen3 at all, because currently, e.g.,
In showVisitSkyMap.py:

butler = dafPersist.Butler(rootDir)

In plotSkyMap.py:

parser.add_argument("skymap", nargs=1, help="Path to skymap pickle")

I personally have found showVisitSkyMap.py very useful, so would be happy to know that it (or an equivalent) is easily available to stack users (although I suspect there are many such implementations in notebooks already in the wild!)

I'm calling this Won't Fix.  Individual scripts may still need work when we retire Gen2, but the extensible Click-based CLI stuff we have in daf_butler provides the reusable components we want, at least for the most part, and I don't think this ticket serves as a useful description of the work to do anymore.

I'm fine with a new ticket for each example script that needs to be fixed up and migrated.

Whether to use click or the argparse recommendation from the developer guide (where the code is put into the main module so it can be tested in both approaches) will be script-dependent I think.