Make tests more comprehensive.

Make error messages more user-friendly. Also remove magic constants
within functions.

Include month and week input types.

Implement setFormValues for easy setting of fields.

Also migrated to pridepack because tsdx is already unmaintained.

The tests do not depend on separate files for loading templates. This is
for the layouts to be defined alongside the tests for easier updates.

The methods have been refactored and documented for ease of use of the
consumers.