Add ability to specify time range and time increment

[robertgodfrey]

Also now displays the time in 12-hr format instead of 24-hr format (just my personal preference).

Examples:

Normal init with default time values:

new DateTimePicker( 'select_datetime', {
  start_date: "2023-04-02T12:30:00",
  last_date: new Date( 2023, 5, 2, 22, 30 ),
  first_day_no: 1,
});

Specify time window from 12PM to 3PM, 10 minute time interval:

new DateTimePicker( 'select_datetime', {
  start_date: "2023-04-02T12:30:00",
  last_date: new Date( 2023, 5, 2, 22, 30 ),
  first_day_no: 1,
  start_hour: 12,
  end_hour: 15,
  time_increment: 10,
});

Specify time window from 9AM to 5PM, with one hour time interval:

new DateTimePicker( 'select_datetime', {
  start_date: "2023-04-02T12:30:00",
  last_date: new Date( 2023, 5, 2, 22, 30 ),
  first_day_no: 1,
  start_hour: 9,
  end_hour: 18,
  time_increment: 60,
});

The rows adjust dynamically depending on the number of time options specified. If there are 12 time options or less, the number of columns reduces from 6 to 4.

Thank you for creating this and let me know what you think! 😁