React SDK: easier tracking of `checked` based inputs

[sdirosa]

This PR is inspired by and (hopefully) solves https://github.com/objectiv/objectiv-analytics/issues/1131

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In this PR I add options to further customize how we track inputs. The main aim is to better support tracking checked based inputs, such as radio and checkbox.

TrackedInputContext

• new prop: attributeToMonitor, with sensible defaults depending on the input type
• new prop: attributeToTrack, with sensible defaults depending on the input type
• Some input validation (mainly to point out conflicting or impossible configurations)
• Support for defaultChecked
• Normalization for checked tracking to our standard '0' and '1'
• Re-enabled triggering events via onChange event for checkboxes and radio (it was a testing fluke)
• Automatically track radio name as ContentContext in LocationStack of InputChangeEvents
• Extended type definition to support HTMLSelectElement + test case

New Components

Leveraging the new capabilities of TrackedInputContext I've added:

• TrackedInputCheckbox
• TrackedSelect

Todo

• [x] Support onChange events for checkboxes and radios. This seems to be an issue either with JSDOM or testing-library, as the behavior when testing manually differs from what happens in unit tests.
• [x] Track radio group name attribute as Location
• [x] Add warning message to TrackedInput inviting to use the new TrackedInputCheckbox and TrackedInputRadio
• [ ] Verify feasibility: support multiple attribute for TrackedSelect or warn if set
• [x] Update documentation
  • [x] TrackedInputContext
  • [x] TrackedInputRadio
  • [x] TrackedInputCheckbox
  • [ ] TrackedSelect
• [ ] Manual testing and QA