Timezones

We were never looking into timezones before. This becomes a problem now that people use ELNs and care about times and not just dates. In prinziple most date formats and libraries support to add a timezone to the date. We just have to ensure that this information is added in the right places. This issue goes through all aspects of the platform.

• ensure timezone when adding dates to the metainfo. Either use information in the given date or use a "configured" time zone?
• add the local browser timezone to datestrings in the GUI. If those are forwarded to the metainfo they are kept.
• when displaying datetimes in the gui, make sure that the datetime is converted to local browser timezone, based on the timezone information in the datetime
• ensure timezone information in dates in mongo and elastic search