Changes to POST /contracts

added the new required request property address

added the new required request property property_id

added the new required request property seller_name

removed the request property Address

removed the request property PropertyId

removed the request property SellerName

added the new required request property Address

added the new required request property PropertyId

added the new required request property SellerName

removed the request property address

removed the request property property_id

removed the request property seller_name