WIP: Feedback attachment

https://github.com/geoadmin/mf-geoadmin3/issues/1522

Current implementation accepts only one attachment.
Similarly to the Import KML, this feature is not available in IE9.

[Test Link] (http://mf-geoadmin3.dev.bgdi.ch/gal_feedback_attachement/src/?X=202235.27&Y=752102.91&zoom=1&lang=en&topic=ech&bgLayer=ch.swisstopo.pixelkarte-farbe)


I thinks you just removed the print :=)

Anyway, why using the proxy? Why not directly using the API with CORS?

Note: the print proxy will eventually disappear when we get rid of the print cookies. The goald is to not have proxy definitions but to use CORS.