Response for returning data points should have stronger typing

[Robin-Hoodie]

Currently, the datapoints.retrieve method returns a response of Promise<DatapointAggregates[] | Datapoints[]>.

This makes things more complicated for consumers than they need to be, as they either have to:

• Type cast the response
• Add their own wrapper method, which does allow for a properly typed response

Consumers should ideally be able to call retrieve without needing to pass a generic type, as the return type can be inferred from the query argument

const datapoints = client.datapoints.retrieve({ aggregates: ['average'], granularity: '1d' , /*...rest of args*/ });
// datapoints is typed as Promise<DatapointAggregates[]>`

const datapoints = client.datapoints.retrieve(/*...args without 'aggregates'*/);
// datapoints is typed as Promise<Datapoints[]>

Going even further, I think it'd also be a good idea to be able to strongly type the types of aggregates themselves.
As in, if we pass aggregates: ['average', 'min'], the response is currently still returning a set of datapoints where both average and min can be undefined, even though we know they are in fact defined.

Thinking about possible implementations, it'd probably make sense to require consumers to pass in a generic type for this possibility. Not requiring that would likely result in a combinatory explosion.

[Robin-Hoodie]

Any feedback on this?