Plotting should support local dates/times

[rbasralian]

It should be possible to plot data by local date/time/datetime without converting it to a zoned datetime (epoch millis/nanos/whatever) first.

For example, the X axis for daily data is generally something like [ '2022-05-05', '2022-05-06', '2022-05-09']. It should be able to plot this, with the gap in the X axis respected, without converting to millis.

Same for times/time offsets (e.g. 10:00, 10:30, 12:00, 14:00, 18:00, 28:00) and unzoned datetimes.

[niloc132]

Should be addressed as part of the catch-all #188 ticket.