Put the kernelside rump kernel headers into <rump-sys> instead of
sprinkling them around the faction directories. Avoids having
to add a CPPFLAGS (or several) to pretty much every component
Makefile.

Leave compat headers around in the old locations.

The commit changes some autogenerated files, but I'll fix the
generators shortly and regen.

branches: 1.2.2;
Use IOCONF #define to determine component name.

Avoids having to manually retype info already in .ioconf.

Also, COMPONENT_SIMPLE -> RUMP_COMPONENT=simple. That way, we can add
other attributes where necessary. As "future directions", the "ioconf"
attribute for RUMP_COMPONENT can just be removed when a driver is
converted to modular and has a proper modcmd.

Make it easier to create rump kernel components, part 1.

Reduce copypasteware for the component constructors. If a constructor
calls only config_init_component(), handle it from a common source file
instead of copying the same(ish) file around to every component.