Integrate Typed Data Widgets

@josephgut
In my case combining the patch here with the patch from #2723259-23: Allow single-valued data selector input to be passed as an array for 'multiple' context fields → helped with both configuring and sending email. I had to adjust the patch from there a bit in order to make it applyable on top of the patch in #174.

dylan donkersgoed → made their first commit to this issue’s fork.

dylan donkersgoed → changed the visibility of the branch 2471481-integrate-typed-data to hidden.

Uploading a patch rerolled for the 4.x version. I pushed the changes to the 2471481-integrate-typed-data-4.x branch as well. It's not letting me open it as an MR right now, but I may at some point in the future. In the meantime here's the patch file.