Expose options types publicly

[benlesh]

I ran across userland code recently where the developer had to copy the BasicGroupByOptions interface into their own code because we don't expose it. If we have an interface for an options/config argument, we should be exposing that type so people can use it.

We'll probably want to make sure their naming convention is consistent prior to exposure.

[jakovljevic-mladen]

But we do expose this interface since v7 🙈. (Which version does the mentioned repo use?)

We expose a lot of configuration interfaces and one of the reasons we do is because the docs app would required them exposed so it can show them in the app. For more info, please check this PR.

I found a couple of PRs where many such interfaces are exposed:

• docs: include additional interfaces to 'rxjs' export site #6733
• docs: document and export TapObserver #6944
• feat(repeatWhen): notifier supports ObservableInput #7103

[benlesh]

Mkay