Support PBS config environment variables like PBS_PRIMARY , PBS_SECONDARY, PBS_LEAF_ROUTERSand PBS_MOM_HOME at install time along with new license config variable PBS_LICENSE_INFO

As an admin, I want to be able to specify a location for my license file at install time, so that I do not have to perform additional copying/configuration steps after installation to have a functional installation.

Ensure initial boilerplate text is still displayed at install time

PBS Pro should not require that all of the directories leading up to the last level directory exist for a value specified for PBS_HOME

As an admin, I'd like to be able to set PBS_MOM_HOME at installation time, so I don't have to go back out to my nodes to set it post-install.

As an admin, I'd like to be able to set PBS_PRIMARY and PBS_SECONDARY at install time, so I don't have to reconfigure my execution hosts post install

As an admin, I'd like to be able to set PBS_LEAF_ROUTERS at install time, so I do not have to do configuration post installation

To tell systemd to start pbs services automatically at boot, you must enable them