Support .uischema for form dialogs schema building

[GeoffCoxMSFT]

The schema returned from bf-generate will have default values for describing the fields for each property added to the schema. These strings will need to be supported for localizing in the client.

• Investigate these options:
• whether to have additions to the SDK schema and UI schema for these types
• if a path modification system could work with the en-US.json in Composer
• if a language specific UI schema should be returned from bf-generate