Arrange for the ionpump pressure rise alarm/shutdown to be ignored.

We added a shutdown trigger for the ion pumps in INSTRM-772. That has a buffer to get past startup impulses, but we also get spikes when, e.g. the gatevalve is opened or the other pump started.

I do not like the idea of always ignoring 60s spikes, and think we should add a mechanism to temporarily pause or modify the shutdown trigger. Could be started when the cooler, gatevalve, or ionpump state is changed.