Add functionality of getting people as an iterator in cht-datasource

[sugat009]

Is your feature request related to a problem? Please describe.

This feature is part of a bigger feature of the creation of API endpoints for getting contacts by type. (#9193)
The target of this feature is to have the functionality of getting people using cht-datasource as an AsyncIterator or something similar that can fetch data in batches.

Describe the solution you'd like

Person.v1.getAllAsync();

Describe alternatives you've considered

Additional context

[jkuester]

As noted here: #9237 (comment)

I think we should go for a function signature like:

const getAll = () => AsyncGenerator<Person.v1.Person, void>

Also, FTR, I have found this blog post to be very helpful in wrapping my mind around async interators/generators.

[garethbowen]

@sugat009 Should this be in the release milestone?

[sugat009]

@garethbowen yes.

[jkuester]

I am removing this from the 4.11 milestone since it is covered already by #9241.