The process finalizing a minute and sending all mails takes some time. As a user I would like to see if there is something going on.

After clicking the Finalize-Button within the finaliz-dialog the dialog should close immediately. Then the "Finalize Minutes"-Button in the upper right corner of the minute should be replaced by a spinner item. If the finalize workflow is done we should show a success message and replace the spinner item again with the correct button.