Extract logic from prov_update_parent_path

This commit removes the actual decision making from the
JSA::Starlink::prov_update_parent_path subroutine.  It now takes
subroutine references to routines from the JSA::Files module, and
new routines in the JSA::Convert containing the code extracted from
the prov_update_parent_path and _check_parent_product subroutines.

This is to allow prov_update_parent_path to be used for archives
other than the JSA, such as the UKIRT Archive.
JSA::Starlink: add provenance strict check option