Remember multi-page form progress for signed in Members #719
Description
There should be an option per form where progress can be saved in a multi-page form if a member if signed in to the website.
This would allow members to come back later to continue and complete the form.
A use case for this would be for long application forms that require evidence to be uploaded. If the person doesn't have the evidence to hand, they risk losing all their progress if they have to leave and come back later once they have the evidence.