VFS messaging/interfacing work stage 1/99. This stage replaces the old

VFS messaging/interfacing work stage 1/99.  This stage replaces the old
dynamic VFS descriptor and inlined wrapper mess with a fixed structure
and fixed procedural wrappers.  Most of the work is straightforward except
for vfs_init, which was basically rewritten (and greatly simplified).

It is my intention to make the vop_*() call wrappers eventually handle
range locking and cache coherency issues as well as implementing the
direct call -> messaging interface layer.  The call wrappers will also
API translation as we shift the APIs over to new, more powerful mechanisms
in order to allow the work to be incrementally committed.

This is the first stage of what is likely to be a huge number of stages
to modernize the VFS subsystem.