Versioning engines default location: the VMS case

OpenSSL engines are tied to the OpenSSL shared library versions,
starting with OpenSSL 1.1.  We therefore need to install them in
directories which have the shared library version in it's name, to
easily allow multiple OpenSSL versions to be installed at the same
time.

For VMS, the change is a bit more involved, primarly because the top
installation directory was already versioned, *as well as* some of the
files inside.  That's a bit too much.  Version numbering in files is
also a bit different on VMS.  The engines for shared library version
1.1 will therefore end up in OSSL$INSTROOT:[ENGINES0101.'arch']

('arch' is the architecture we build for)

Reviewed-by: Rich Salz <rsalz@openssl.org>