Add coronagraph position measurement calibration step (and template?)
From email conversation with Pierre Baudoz:
HB: We plan to measure the coronagraph position only once in commissioning and use that forever, is that good enough?
PB: No, I don’t think this will be enough. Coronagraph position can be measured in the target acquisition template (using flat lamp).
We should add such a calibration step. The template can probably be reused.