Support product data (and dicts)
Handle product_data in import/export
Switch format of outputted fixture data

From:

<product_data>
  <data key="num">1234</data>
</product_data>

To:

<product_data>
  <num>1234</num>
</product_data>
Make product_data a real model property
Only add product_data node if there is data
Add test for product_data in fixture
Add UI for product_data
Cleanup
allow selected operator for form action conditions
allow use of 'selected' operator for form action conditions on UI
fix suite entries to reference configure_entry_* directly

dynamically generating names makes it impossible to do a text search for usage
Put custom product data behind feature flag
UCLA reports: Patient target dates calculations will be processed by signals now.
Hided CommTrack roles in mobile worker settings tab.
fix parsing of @bind (instead of @nodeset) on xform inputs
remove references to hqbilling in corehq
Merge pull request #3629 from dimagi/fix-@bind

fix parsing of @bind (instead of @nodeset) on xform inputs
remove HQBillingAddress and HQBillingMixin
delete payments submodule
remove reference to HQBillingMixin in domain doc