provide simple instructions for updating software at KPNO

[sybenzvi]

We have instructions for upgrading software at KPNO using the GitHub mirror, but we are missing simple instructions to install new versions of desihub packages. We need instructions on the Survey Ops wiki to:

• Document the setup of the KPNO software environment for the datasystems user.
• Document the use of the bootstrap.sh script, which calls desiInstall, using INI files to specify package upgrades and versions.