Make tests more comprehensive.

Include tests for duplicate values, as well as comprehensive date tests.

Correctly set fields when they are arrays.

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.

Use correct description.

Handle selects, as well as file uploads.

This commit adds Cypress for testing the library against a real DOM.