Simplify WorkPoller: drop SQL params, which are constants.
Merge branch 'da-updates' into dev
Merge branch 'da-drop-params' into dev
da: Fix WorkPoller WS output of adjusted priority field
da: Drop inadvisable FIXME for logging adjustments
da: Add instance column migration
da: Add reserved (date) column migration
da: Add reserved not in index_next_visit index migration
da: Add WorkPoller.do_reserve setting, criteria
da: Add WorkerPoller.instance wrap_with_update, tests
da: Adjust with update (reservation) query to return original adjusted priority
da: CotentWriter > ContentReader, move isolation support to Reader, selectWithRetry
core: Add WorkPollStrategy.discard, use in VisitManager; orders, hosts access
da: Implement WorkPoller.discard; test
da: WorkPoller.instance_unreserve (un-integrated); test
core: discard independent of doWaitOnGeneration, drop q, sync in shutdown
core: GenericWorkPollStrategy support false shouldReplaceQueue
da: Support for shouldReplaceQueue -> false if reserve, current_urls
core: VisitManager.doWaitOnGeneration default true (adjust test)
da: Fix wrap_with_update: uhash required; test