separate statement timeout for "maintenance" queries
similar to #450 (closed) / !466 (merged)
some operations that run in background perform queries that may take a long time to complete (the most commonly noticed one is CleanRemoteFilesProcessorService
)
we may set a different timeout (very long, or unlimited?) for those
complication: there doesn't seem to be a way to change the statement timeout per query (the TypeORM docs don't mention it, some web searches have returned nothing useful and strong hints to "can't be done"; plus, it may not actually be possible without messing with the postgresql driver directly)