Available options:
* widget: How to render the time field ("input" or "choice"). Default: "choice".
* type: The type of the date stored on the object. Default: "datetime":
* datetime: A DateTime object;
* string: A raw string (e.g. 2011-05-01 12:30:00, Y-m-d H:i:s);
* timestamp: A unix timestamp (e.g. 1304208000).
* raw: An hour, minute, second array
* with_seconds Whether or not to create a field for seconds. Default: false.
* hours: An array of hours for the hour select tag.
* minutes: An array of minutes for the minute select tag.
* seconds: An array of seconds for the second select tag.
* data_timezone: The timezone of the data. Default: UTC.
* user_timezone: The timezone of the user entering a new value. Default: UTC.