In supervised nodes, the Supervisor's NodeConfig$scripts vector adds scripts to
the end of the user-provided scripts (options.scripts_to_load), so they load
_after_ any user-provided ones. This can cause confusing redef pitfalls when
users expect their customizations to run last, as they normally do.
This adds two members in Supervisor::NodeConfig, `addl_base_scripts` and
`addl_user_scripts`, to store scripts to load before and after the user scripts,
respectively. The latter serves the same purpose as the old `scripts` member,
which is still there but deprecated (in scriptland only). It functions as
before, after any scripts added via `addl_user_scripts`.
