[IMP] formio: Possibility to redirect the (parent) window upon submit of embedded public form.

[bobslee]

Possibility to redirect the (parent) window upon submit of an embedded public form.

The redirect occurs if the <iframe/> has set:

• URL query-param ?embed (any value allowed).
• Following sandbox attribute with values (AFAIK): sandbox="allow-same-origin allow-scripts allow-top-navigation"