Hubspot: Support incremental sync on all possible streams

[sherifnada]

Tell us about the problem you're trying to solve

The Hubspot API supports incremental sync for many more objects than we currently offer via our connector. Many streams (e.g: products) are using full refresh sync when they could be doing incremental.

Describe the solution you’d like

1. Find which streams can support incremental sync
2. Support incremental sync for as many as possible

[lgomezm]

Hello! I've been exercising this solution as we need incremental updates to handle one of our use cases, but I think the current solution won't scale for big Hubspot accounts. That is because it iterates over the the complete dataset (say contacts) and outputs only those that were created/updated after the given state.

I would be more than happy to take on the task of updating this connector and, in fact, I already have a branch in which I am applying a different approach on some of the available streams. If that's okay with you guys, I can create a draft PR (will add tests shortly and update all other necessary files).

[sherifnada]

@lgomezm nothing we love more than a contribution! let us know how we can be helpful, @lazebnyi can work with you to get it into master :)