[CAL-3250] Assign recurring round-robin events to different hosts

[CarinaWolli]

Right now, the same round-robin host is assigned to every recurring event instance. There are use cases where it makes more sense to assign different round-robin hosts for every instance. We want to allow the users to choose in the event-types settings how the hosts should be assigned.

_{From SyncLinear.com | CAL-3435}

[muskan2622]

Do you want to do the changes here??

[CarinaWolli]

Tagging @ciaranha for design