Set NEVERLVNULLSUBS correctly for VistA

VistA doesn't allow null subscripts and uses null subscripts in $Order
commands where null subscripts can cause errors.

The gtm_lvnullsubs environment variable controls the behavior of null
subscripts. 2 is the value for NEVERLVNULLSUBS.

Documentation:
http://tinco.pair.com/bhaskar/gtm/doc/books/pg/UNIX_manual/ch06s27.html#ch6_lvnullsubs
Remove unnecessary files

Most of these scripts clone repositories and make configuration changes
that are replicated in other scripts and thus unnecessary.
Rearrange Common directory

Most of the scripts under common were actually GTM specific - move them
to the GTM directory.

configureCPRS.sh should be common as that just opens firewall ports
which isn't platform specific.