feat: manage recurring messages

[luca-montaigut]

Renamed branch for #45

Manage recurring messages with con job:
/recurrent +

• add : recurring message daily / weekly / monthly
• remove : recurring message
• list : recurring message

[neolectron]

I think cron messages should be handled by the core instead of per-feature.
So we can manage where we store/restore them.
It would also remove the need for any other feature that needs cron to create a redis key, etc etc.
What do you think ?

[luca-montaigut]

I think cron messages should be handled by the core instead of per-feature. So we can manage where we store/restore them. It would also remove the need for any other feature that needs cron to create a redis key, etc etc. What do you think ?

I think it will be a good idea when we will have another feature that need cron. Same as the last refactoring, it was relevant because it really corresponds to our features and not to an hypothetical future.

We also have a topic regarding permissions on commands (ex: isModo)

(PS : I will apply change to this PR to match quoi-feur suggestions)