Import speaker image from sessionize

[ceciliasharp]

Today we are showing the url to the sessionize speaker image on the backoffice speaker page and there is a function to upload a speaker image there as well. But the workflow now is save the image -> upload image. We need to streamline that to just "upload sessionize image". Function to upload selected image for the speaker needs to still be there in case of a change or manually adding a speaker.

[ceciliasharp]

On the Speaker object there is a field called SessionizeImageUrl that contains what we need. An embryo of the function needed is called "SaveImageFromSessionize" and located in the SpeakerAdminController