VMS build changes

crypto/crypto-lib.com:
 Remove all APPS building, as they are gone.
 Depend on the variable SDIRS that's defined by makevms.com.
 Remake the whole partial module list mechanism to check for variables with a counter.
 Define the logical name INTERNAL to allow for '#include "internal/foo.h"'.

makevms.com:
 Define SDIRS, to allow for removal of crypto modules and pass that information to crypto/crypto-lib.com.
 Allow for experimental modules.
 Update the allowed things to disable.
 Update the things disabled by default to match Configure.
 Update headers to be copied.

Reviewed-by: Andy Polyakov <appro@openssl.org>