WatchedItemStore: Use batching in setNotificationTimestampsForUser

WatchedItemStore: Use batching in setNotificationTimestampsForUser

Update rows in batches, using the same logic as is used by
removeWatchBatchForUser().

Also remove the functionality for updating all rows, and move that to
resetAllNotificationTimestampsForUser() instead. To that end, add a
timestamp parameter to that method and to the job it uses, and make
setNotificationTimestampsForUser() behave like a backwards-compatibility
wrapper around resetAllNotificationTimestampsForUser() when no list of
titles is specified.

Bug: T207941
Change-Id: I58342257395de6fcfb4c392b3945b12883ca1680
Follows-Up: I2008ff89c95fe6f66a3fd789d2cef0e8fe52bd93