suzerain: move PP sequences out of classes

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@43647 0bd85f0b-c151-43b9-a1e9-27231104551f
suzerain: #2736 isolate PP definitions

Makes it a bit easier to work with the data-driven aspects
of these classes and to test.

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@43648 0bd85f0b-c151-43b9-a1e9-27231104551f