Build all forms using the Form service

[hellopablo]

$oForm = Factory::service('Form') provides methods for generating distinct form components. Use this over the CI form_* functions.

Things to do:

• Capable of generating all form elements
• Tests written
• Used by Nails\Common\Helper\Form and Nails\Common\Helper\Form\Field
• Model Base should define fields using the Form service constants
• Remove use of form_* functions
• All Nails views should use the service
• Remove Nails\Common\Helper\Form
• Move Nails\Common\Helper\Form\Field to module-admin

And maybe some more too, basically this is a big change with the goal of removing dependency on CI for generating these fields.