Use more HTML5 input types

We only use type="number" for now.

I think it would make sense to use types email, url and tel as they fallback without problem to a text input and will provide a better interface on some browsers.

We should also use type=search for search fields (may improve experience on phones).

The hard decision is whether to replace our date input by the type=date HTML5 input. Here is the support matrix: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input/date#Browser_compatibility

All major browsers seem to support it, and I expect most of them will have a better interface than our old fashion datepicker. It would mean switching from d.m.Y to YYYY-MM-DD format for POST value. We may keep d.m.Y as internal value to avoid confusing webservice and internal code (but I do think YYYY-MM-DD is a better and more widely used format).

For outdated browser, they would in this case show a text input field and users would have to "guess" they need to enter YYYY-MM-DD format. We can detect this case in javascript and maybe add a text to explain this, or even try to add the old datepicker (but that means adapt its code to support YYYY-MM-DD format). We can use pattern attribute to force NNNN-NN-NN format (with N an integer), which is more widely supported (IE>=10).

Actual behavior

inputs are using types text, select, url, button and number

Expected behavior

Use email, tel, search, date types.