REST call to retrieve pointing model

[wfarah]

Request: a REST GET method to retrieve pointing model (TPOINT coefficients + other parameters as seen in the PointingModel_antXX.dat files) for antennas in json format. They are needed to apply the pointing corrections and needed when observations are being taken.
I can then write python to wrap around them

[wfarah]

Call will be plugged here:
https://github.com/SETIatHCRO/ATA-Utils/blob/master/pythonLibs/ATATools/ata_pointing.py

[tkoumrian]

I've added the REST call, and linkage in PointingModel. This only populates the TPOINT coefficients, since that's all you had, but the entire set of parameters from the pointing model files is available from the REST call.