Switch to cross-platform adduser/addgroup
Switch to cross-platform adduser/addgroup

useradd/groupadd is Debian specific and doesn't work as expected on
other Linuxes (CentOS).

add $instance to username so multiple instances can be on one machine.

mdgeek/VistA-FHIR-CWF,josephsnyder/VistA,OSEHRA-Sandbox/VistA,OSEHRA/VistA,shabiel/VistA,apexdatasolutions/VistA,jasonli2000/VistA,mdgeek/VistA-FHIR-CWF,OSEHRA/VistA,timmvt/VistA_tt,jasonli2000/VistA,mdgeek/VistA-FHIR-CWF,mdgeek/VistA-FHIR-CWF,mdgeek/VistA-FHIR-CWF,timmvt/VistA_tt,jasonli2000/VistA,shabiel/VistA,OSEHRA-Sandbox/VistA,OSEHRA/VistA,josephsnyder/VistA,apexdatasolutions/VistA,OSEHRA/VistA,OSEHRA-Sandbox/VistA,OSEHRA/VistA,shabiel/VistA,jasonli2000/VistA,timmvt/VistA_tt,timmvt/VistA_tt,timmvt/VistA_tt,apexdatasolutions/VistA,OSEHRA/VistA,mdgeek/VistA-FHIR-CWF,shabiel/VistA,OSEHRA-Sandbox/VistA,OSEHRA-Sandbox/VistA,OSEHRA-Sandbox/VistA,shabiel/VistA,josephsnyder/VistA,josephsnyder/VistA,apexdatasolutions/VistA,josephsnyder/VistA,josephsnyder/VistA,apexdatasolutions/VistA,shabiel/VistA