Restore help tooltips

[etj]

When editing a dataset, there's a space between every upper input and the lower label

that is a badly rendered <span> info tooltip:

By replacing the proper fa fa-info-circle in place of the old icon-info-sign I get this:

• [ ] The info icon should be placed close to the relevant input label
• [ ] When hovering, the tooltip should be displayed

[etj]

Macro help_block --> https://github.com/geosolutions-it/ckanext-dcatapit/blob/1292090c0c222415cc5e0ad14a2d370c2a3f29fc/ckanext/dcatapit/templates/macros/dcatapit_form_macros.html#L473-L479

The macro is only called within the same file.

Related js should be at https://github.com/geosolutions-it/ckanext-dcatapit/blob/1292090c0c222415cc5e0ad14a2d370c2a3f29fc/ckanext/dcatapit/fanstatic/dcatapit.js#L577-L587

[etj]

I guess that most of the macro code has been taken from an older version of CKAN.
See https://github.com/ckan/ckan/blob/ckan-2.9.5/ckan/templates/macros/form.html#L338-L345