Save panda should ignore DATA PV'S

As a PandA user, I would like to load a panda yaml file after creating my PandA device. Some PV's which are correctly configured during device creation are then overwritten by this yaml file. Since these PV's are configured for us, we never want these saved and loaded

Acceptance criteria

- `save_panda` utility function ignores all PV's which start with the string 'DATA'. (Try saving a panda and looking at the yaml output to see these data PV's. `ophyd-async`'s generic save function accepts a list of signals to ignore.