associate timezones with all timestamps recorded in provenance tables
Right now provenance records timestamps in local time without recording timezone. This is lossy. E.g. one problem scenario: User runs a workflow on their laptop in one timezone, moves timezones, and exports the run. The exported run now has the wrong timestamp recorded. Related is that WRM is assuming local timezone and during run-export, adding the local timezone in the recorded run (separate bug).
Part of this bug is to also deal with a user's existing timestamps. While it's not safe to associate local timezone to all their existing timestamps, it's the best guess we can make, short of giving the user a way to change them. The user should at least be made aware this is what's going to happen during the provenance schema upgrade.