EST-416: tidying up integration tests, to use nested static classes.

There are no instances of LocalDate.now() to fix.
EST-439: decouple RemoveEvent using the put/get hash
EST-440: removing only call in production code to EstatioInteractoinCache, replacing with call to QueryResultsCache.
EST-440: fix for unit test; deleting EstatioInteractionCache
EST-230: converting unit tests into nested static format.
EST-230: converting unit tests into nested static format.
EST-230: finished converting unit tests to nested static class format.
Person class
EST-408b: Class Organisation/party
EST-408b: Classes BankMandate, Lease and Guarantee which all extends class Agreement
EST-408b modify bank account