Updated move destination widget to hide closed dossiers.
Fixed typo at workflow name in mock test.
PEP8.
Replaced hardcoded workflow names with constants.
remove commented code introduced with be77020

This check was uncommented for some time...
I don't think it's necessary to keep it around.

Original: d49d8c096cc7d4479839d4bee751c0a41512da0e
Comment: be770204e2de7ff71a958bb3661debb69c9841d8
Removed IMailInAddress behavior. Not needed any more with ftw.mail 2.0.
Provide an IntIdResolver adpater to generate Dossier Mail-In addresses

based on IntIds, and use it instead of the old implementation.
Removed og.mail IMailSettings registry interface (now done in ftw.mail).

Added upgrade step to migrate settings to ftw.mail's IMailSettings and
remove old og.mail IMailSettings.
Hide standard ftw.mail mail-in viewlet (we display the mail address in the byline).
Update mail related tests.

- Mails can't be added inside tasks. Neither directly nor via mail-in.
- Expected mail domain should be set in test itself
Use ftw.mail from source until we create a KGS that uses >= 2.0.