dateProxy : time format can't have seconds

[pierre-H]

Is your feature request related to a problem? Please describe.
The dateProxy with the time type only returns hours and minutes. No seconds (possible in HTML with the step attribute).

Describe the solution you'd like
Add a step param. If it is less than 60, display the seconds.

Describe alternatives you've considered
Create the proxy myself.

[ciscoheat]

Added now in 2.23.0, though using only time as format could cause problems as the date part of the date will be set to the current day, not taking UTC into account. time-utc could be better, but the best thing would probably be to treat time fields as a string and parse them manually.