Make scripts flexible for multiple environments

InstallVistAinUserAccountForGTM made many assumpions about the
environment:
 - Installed in user's home directory
 - Separate scripts for 64/32 bit
 - Relies upon GTM defaults for VistA configuration
 - Hard coded GTM path

The new script detects 64/32 bit and makes appropriate changes, locates
GTM directory using LSB directory defaults (not GTM version dependant),
setup to deal with multiple instances of *VistA on one machine.