Add state TTL/expiry to Add/Set in actor state manager

[andrew-goldie]

Is your feature request related to a problem? Please describe. We have a couple of use cases where actor state needs to expire reasonably quickly. In the general state store, setting a ttl is possible but this is not exposed in the Actor state management API (go-sdk).

Describe the solution you'd like Allow state metadata to be passed in to Actor state management.

Describe alternatives you've considered

• Use a timer (this is what I will try next).
• Fall back to using general state management which has metadata access, constructing per-actor keys.
• Set actor lifetime to quite short and clear state on deactivation callback (is this even possible?)