(TK-2) Add in prismatic schemas and tests for configuration objects

This commit adds prismatic schema definitions and tests for all
of the objects making up the jetty9 configuration.  It doesn't
actually wire the schemas into the code yet.
(TK-2) Remove old `configure-webserver` functions

This commit removes all of the old configuration functions and
ports the code to use the new prismatic schema representations
of the config data.
(TK-2) Reorganize core namespace

This commit doesn't contain any code changes; it simply re-orders
the functions and adds some pragmas to try to make things a bit
more organized.