Purpose of this commit is to allow moderation on incoming messages in
discussion channels. On some channels on which moderation is required
messages should be in a pending moderation stage. Moderators can accept
or refuse messages as well as always allow or ban messages coming from
a given set of emails.
Channels now have an option to be moderated. Moderators can be added on
channels. They have access to a specific UI in Discuss to see and take
action on messages waiting for moderation.
Concerning mail.thread message that are pending moderation are not notified.
It means nobody receives a notification about them. Moderation process calls
the notification once the message is validated.
Various features included in this commit :
* a model is added to store the decision about emails, allow or ban;
* access rights are updated so that only moderators can modify moderation
fields on message;
* specific bus notifications are send to moderated people as well as to
moderators on incoming emails as well as when a decision is taken;
* options are added on channels to send explanations to moderated emails;
* options are added on channels to write and send guidelines explaining
why and how moderation is performed;
* a reminder is send daily to moderators with remaining messages to moderate;
* discuss UI is adapted and a new channel is added below Inbox and Starred
giving access to moderation tools;
* chanenl UI is adapted allowing to moderate directly inside channels;
This commit is linked to task ID 29521. Closes#21921.
Mathieu Duckaerts-Antoine