Bug 1129937

During testing of jsc#SLE-2995 and playing editing form.yml to create different visualizations, it was found that:

- Validation are missing for types: `number`, `url`
- For `date` even there is a visual validation, we can put cursor at the end and go backward writing '9999-99-99'. 
- Dialog with error validation only contains the first error found, instead of a list of them.

It is easy to check using a small portion of this example:
https://github.com/yast/yast-configuration-management/blob/master/test/fixtures/formulas-ng/test-formula/form.yml

Expectation:
An error is displayed if something that is not a number is introduced in that field, the same for url. Date field should avoid that specific trick and be validated. Regarding usability, give errors one by one perhaps not the best choice, I note that only just as an observation.