Allow restoring deleted groups (&suppliers)

[wvengen]

Sometimes members leave. But they may come back. Especially when a member has paid a membership fee before, it would be nice if the system wouldn't just forget that.

Right now:

• Workgroups are deleted irrevocably
• Ordergroups are marked as deleted

I propose that also:

• Ordergroups are deleted if there's no financial or order history when marked as deleted
• There will be a "deleted ordergroups" list, accessible from the ordergroups overview
• When a new ordergroup is created with the same name as a marked-as-deleted, Foodsoft gives the option to revive the ordergroup (see Cannot create supplier or group with same name as deleted #197).
• An admin can invite a new email address to a deleted ordergroup, and after success the ordergroup will be active again.
• When a group is deleted, Foodsoft proposes to delete users who have no other groups

[marcopenhacking]

Ordergroups are deleted if there's no financial or order history when marked as deleted

That are probably just the new and unused ordergroups which should be very seldom.

• Ordergroups that are marked as deleted may need to be renamed - see Cannot create supplier or group with same name as deleted #197.
• Should there be a way to completely delete an ordergroup marked as deleted (in "deleted ordergroups list")? I think if it's possible there should be a way to delete it to avoid unnecessary grow of the database. But then all the orders of that ordergroup need to be deleted as well and probably some other related information in the database. This is probably another possible feature (maybe needed after running foodsoft a couple of years .. not for us in the moment).

[wvengen]

That are probably just the new and unused ordergroups which should be very seldom.

This happens now and then for us. We have quite some members that signed up (using a public form), and ended up not participating. Not having any order, they could just be deleted. Not a very pressing feature (but useful nonetheless, and not too complicated).

I'd be careful with deleting group orders, since that messes up order history.

[wvengen]

similar to #406