Package create form wizard

[icmurray]

Create the form wizard for the package-new form.

Each section of the form will be a separate page as this was decided to be simpler than the alternative of making AJAX calls for validation at each stage. (*)

• separate pages for each section of the form
• validation carried out at each stage against the whole schema. Each section/page declares a list of schema keys that need to validate for that section to validate, and thus move onto the next section.
• no draft saving to be performed in this ticket.

(*) - although the javascript alternative will probably provide better UX (each step would require a page-load in the wizard approach), it was decided that:

• with the javascript approach it would be harder to test the workflow.
• with the javascript approach there would be additional work displaying validation correctly. Although not that complicated, it was felt to add another point of failure.
• the multi-page wizard is quicker and easier to implement, and if it provided poor UX, then the javascript approach would be used instead.
• the multi-page wizard wouldn't preclude a javascript-tabbing create-form for other cases (where the wizard workflow wasn't such a good match, eg on the hedatahub.org)
• the multi-page wizard wouldn't preclude a javascript-tabbing edit-form.