IOC: Discuss ways of setting intial setpoints

[John-Holt-Tessella]

As an instrument scientists I would like the intiial setpoints to be set to the set point reaadback on IOC start. As a developer this seems hard discuss how to do this and whether it is desirable given the answer.

We should cover:

1. Single readback from device
2. Multiple read back sp (i.e. in a status string)
3. Calculated setpoint (i.e. as a result of calibrartion)
4. Multiple setpoint combinations
5. No readback from device
6. What happens if user changes device on its front panel. (when editing and not editing set point)
7. Is it better to be consistent or cover most cases?

[LilithCole]

Would possibly resolve #5706