Issue 385: flexibility with running strict unit validation

[fbergmann]

Description

This PR adds the strict unit validator to the options, so it can be run using checkConsistency. Additionally it adds an override flag to checkConsistencyWithStrictUnits, so that callers can decide as to the status of unit issues.

The PR is written so that the behavior with it is the same as before:

• callers have to explicitly enable StrictUnitsCheckON with setConsistencyChecks for it to be run with checkConsistency
• the test shows the behavior of both modes

Motivation and Context

fixes #385

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Change in documentation

Checklist:

• I have updated all documentation necessary.
• I have checked spelling in (new) comments.

Testing

• Testing is done automatically and codecov shows test coverage
• This cannot be tested automatically

[matthiaskoenig]

Thanks. This is great.