effulgentsia

refs #1595298 Revert CSRF token checks back to page callbacks, not menu access callbacks.

This will be refactored again later when the routing system is upgraded.

Improve system path handling and use the system path to determine if we need to show a custom theme.

#1536844: Moved language, path, theme, and module initialization from bootstrap to request listeners.

Decouple plugin types from discovery patch

This replaces the kernel with plugin types. It turns out if a plugin type isn't
the discovery and kernels are per type then really, they're just the type. In
the kernel type model developers wouldn't really be making kernel types but
there will probably be types created more often.

This is definitely a work in progress still.

First step in #1529162