Services to compute ephemeris and related times.

There are two RDs in here: times.vord and res/apfs_new.vord (the latter
could be moved up, but that would break URLs).

In both cases, we could easily cut out the middleman (i.e., the FORTRAN
program).  It's basically there because we wanted Helmut to have the
responsibility.  Now that he's retired, we way want to port the whole
thing over to SOFA (i.e., astropy)