[BNSI-7664] Extract uncounted (0-stock) handling per storage place into a...

[BNSI-7664] Extract uncounted (0-stock) handling per storage place into a separate function. Improve error logging. Ensure blocking of concurrent requests for FinishStockTaking by signaling FINISH (setting inventory.enddate) and reversing signal FINISH (inventory.enddate = NULL) on failure to finish stock taking.