Seperate Thermocouple Calcs to New File

[jjderooy]

Description

Right now, Aidan's thermocouple code is just dumped into read_labjack.py. I think it would make more sense to make a thermocouple.py that contains the function get_ref_voltage() and V_to_K(). Then we import this into read_labjack.py and use as needed.

Acceptance Criteria

• [x] Create new file called thermocouple.py that contains the V_to_K() function currently in read_labjack.py.
• [x] Remove current thermocouple code from read_labjack.py and import the functions in thermocouple.py to replace them.
• [x] Add some comments in thermocouple.py that describe where the function parameters came from, units etc.

Dev Notes

QA Notes

Linked issues

[jjderooy]

See comment on #35. This is pretty much ready to go, there is just a small (~7K) temp discrepancy right now that I haven't been able to resolve yet.