Assign Terminal to merchant

[StuartFerguson]

REST endpoint that alllows the assigning of a physical terminal to a merchant

Payload:

TerminalId (guid of physcial terminal)
AcqurierMerchantId (string)
AcquirerTerminalId (string)

REST url - POST api/estates/{estateid}/merchants/{merchantid}/terminals

This uri will return an HTTP Created Response with a payload TBC