Feature Request: Validation

[zieglerSe]

In special cases, used values lead to the cancellation of jobs. Examples are mentioned in #1 .
To solve this, a Validation module should be implemented.
In my opinion, two types of validation are required.

1. One, which returns error messages to the user and informs that those values have to be changed.
2. A module that automatically sets the problematic values to a default value, which helps to automatize processes using Slurmi (e.g. CWL to Slurmi). In the second case, no direct user interference is planned, hence the default values.