Allow European configuration

[sebashine-branly]

• I'm submitting a ...
  [ ] bug report
  [x] feature request
  [ ] question about the decisions made in the repository
  [ ] question about how to use this project

• Summary

First things first, thanks for this useful package.
I was wondering if there are any plans to support the European aspects of Hubspot. More particularly, I see two obvious spots:

• in HubspotProvider being able to provide a boolean as a prop (which would default to false for backward compatibility) which, when true, would use https://js-eu1.hsforms.net/forms/v2.js instead of the current https://js.hsforms.net/forms/v2.js (line: https://github.com/aaronhayes/react-use-hubspot-form/blob/master/src/HubspotProvider.tsx#L29)
• in UseHubSpotFormProps adding an optional field region which accepts either na1 or eu1 as specified on this documentation page: https://legacydocs.hubspot.com/docs/methods/forms/advanced_form_options (line: https://github.com/aaronhayes/react-use-hubspot-form/blob/master/src/index.ts#L23)

• Other information (e.g. detailed explanation, stacktraces, related issues, suggestions how to fix, links for us to have context, eg. StackOverflow, personal fork, etc.)

In the meantime, I'm using this other package to get this flexibility. However it's not an ideal solution.

Any reply is appreciated. Thank you! 🙏

[aaronhayes]

Happy to accept PRs

[fostimus]

Started a PR: #51