Allow to define a template with defined approvers and use it with minimum approvers requirements

It's currently possible to use Change Request with templates and page created with those templates will have the xobjects defined in the template, so if a template has a list of approvers, the created page will also have it.

But this works only if there's no configured requirements on the minimum lists of approvers: in such case the modal for saving the changes requires to specify the approvers. Right now, this field is not automatically populated by what's found in the template. Meaning that any approver provided in the modal override the list of approvers found in the template.

We should improve that to ensure that any list of approvers found in the edited page is displayed in the modal so that the user can change it before saving.