Feature : configure RebootProgram to allow scontrol reboot

RebootProgram is not defined in the slurm.conf. Configuring it will allow scenarios in which you need to reboot a node without SSHing in it.
Here an example of the command line which will also drain the node from a slurm pov.

`scontrol reboot ASAP nextstate=resume reason="freq-throttle recheck via RebootProgram"`

To be added in slurm.conf or included one :

`RebootProgram = /sbin/reboot`

Start by locating where the project generates or includes slurm.conf and review how other Slurm configuration settings are added. Add the RebootProgram setting with /sbin/reboot, then verify that the resulting configuration supports the shown scontrol reboot command.

Written by the indexing model from the issue text.