feat: want better documentation around jenkinsfiles

[qdzlug]

Is your feature request related to a problem? Please describe. We use a number of variables in the jenkins files for our CI work, and most are not documented. We need to document the variables and also probably put a bailout in the jenkinsfiles so they abort if the variables are not set.

Describe the solution you'd like Documentation.

Describe alternatives you've considered None.

Additional context None.