[Snails] Added missing include.
[Snails] MessageListActionsManager stubs.
[Snails] Better initialization.
[Snails] Instantiate MessageListActionsManager.
[Snails] Pass MessageListActionsManager to MailModel.
[Snails] Generate mail list actions for messages.
[Snails] Return message actions for MessageActions role.
[Snails] Added MessageListActionsProvider.
[Snails] Added Bugzilla messages actions provider.