add support for TTL and time/interval formats in actor timers/reminders

[dmitsh]

Describe the proposal

This feature in implemented in dapr runtime: dapr/dapr#2906

It should be added to the SDK.

Once implemented, it will also resolve #569

Also, add integration tests validating this feature in SDK.

[Giovds]

I would like to give this one a shot if no one is currently working on it.

[Giovds]

/assign

[artursouza]

@Giovds I am moving this to the next release. Please, let me know if you need any help to close on this one.