Catch sqlite timeout & forward queries to CalCat

This should cope better if there are GPFS issues which mean the database stays locked for longer than it should (as we think caused https://redmine.xfel.eu/issues/163349 ).

Of course, if GPFS is very slow, that's likely to be a problem for calibration anyway, because the raw data, the output and the constants are all on GPFS. But this might help if there's a very temporary issue.