Create result requires that I provide UTC time

[adamarnesen]

Trying to call create_test_result with the following code will throw an error that the start and end times have to be in utc. The python API should allow me to provide local time and internally convert to utc.

test_result = TestResult(
        name="name",
        start_date_time=datetime.now(),
        end_date_time=datetime.now(),
        outcome=Outcome.PASSED,
    )

AB#3746793

[hunter-ni]

Some initial notes from assessment:

1. The datastore-python code calls to the hightime_datetime_to_protobuf helper conversion function to get the PrecisionTimestamp needed to send over the wire to the server.
2. The hightime_datetime_to_protobuf method in ni-apis-python calls to convert_datetime.
3. The convert_datetime method in nitypes-python calls to construct a nitypes.bintime.DateTime representing the Hightime.
4. nitypes.bintime.DateTime only supports UTC. Consequently, the call in the constructor to _to_offset throws an error about the timezone needing to be UTC.

Given that nitypes.bintime.DateTime is only intended to support UTC, then I suppose that leaves three main options for where to make a change:

1. The N places in datastore-python where we are calling hightime_datetime_to_protobuf (converting to a UTC Hightime each time before calling this method)
2. Within hightime_datetime_to_protobuf in ni-apis-python
3. Within the convert_datetime logic in nitypes-python

CC @csjall