Feature request: `Range` iterator with `Step` for `NaiveDateTime`

[seongs1024]

Iterating over time range will give a great experience!

NaiveDate has iter_days() and iter_weeks() functions. But in case of NaiveDateTime, it seems necessary to set step_by() to use UNIX timestamps because the period is unknown when iterating over the range.

The request is as follows:

let ts_fmt = "%Y-%m-%d %H:%M";
let start = NaiveDateTime::parse_from_str("2023-02-22 00:00", ts_fmt).unwrap();
let end = NaiveDateTime::parse_from_str("2023-02-23 00:00", ts_fmt).unwrap();
let step = Duration::minutes(15);

// HERE
let lists = (start..end)
    .step_by(step)
    .map(|ts| {
        format!("HELLO: {}", ts);
    })
    .collect();

[seongs1024]

By the way as of now, the feature can be implemented like below:

let lists: Vec<NaiveDateTime> = (start.timestamp_millis()..end.timestamp_millis())
   .step_by(step.num_milliseconds() as usize)
   .map(|ts| NaiveDateTime::from_timestamp_millis(ts).unwrap())
   .collect();