Add basic data QA checks at acquisition

The ccdActor has the actual image in RAM before writing it to disk, so should perform reasonable QA checks right then. In particular, it should check overscan level and noise for each amp.

This would have caught the misconfiguration from the 2020-12-17 work sooner than 2020-12-23...

Reported on some keywords. I think we'd like this to make it out to STS, so I propose at least: visitQA=$visit,status, where status is the usual "OK" vs. "something informative".

Do we also want overscanLevels=8*float and overscanNoise=8*float? No harm in it I don't think, but gets into choices: smallish rectangle, remove drift/tilt, or live with stats on whole thing? Etc.

Note that this touches on the warning-vs-error-vs-critical topic.