This commit introduces three helpers to ignore dates, uuids and paths when using cmp.diff() method
The cmp library has two advantages: - it shows diffs between compared values - it allows ignoring fields based on field name or type
The helper functions in both api packages were more or less same. However, over time they have been slowly diverging. This commit extract the helpers into one common package to make the tests more maintainable and to deduplicate the code.
