DurationFormatter: Digital Data Provider SourceDataProvider impl

[kartva]

Will add bakeddata and testdata in separate PR.

Follow up to #5186.

[younies]

Good job, add the result of cargo make testdata

[kartva]

Note that es-CL has inconsistent hour padding for hm and hms:

"durationUnit-type-hm": {
  "durationUnitPattern": "h:mm"
},
"durationUnit-type-hms": {
  "durationUnitPattern": "hh:mm:ss"
},

[younies]

Good code.

[younies]

this can be optimized, but we can do it in another PR: @kartva , just file a but to optimize this.

[kartva]

To clarify, you are recommending that I file an issue about optimizing this?

[sffc]

I think @younies intended to say "file a bug", so yes. Alternatively, if you already have an issue where you are tracking follow-ups, you can add it there.

[sffc]

This should be easy to bitpack: I think the only possible values are

pub enum HmsPadding {
    None,
    Hour,
    Minute,
    Second,
    HourMinute,
    HourSecond,
    HourMinuteSecond,
}

Are there any locales with patterns such as the following? If not, we can cut down the options further:

• h:m:ss
• h:mm:s
• h:m:s
• m:s

Then I think the only options are

pub enum HmsPadding {
    None,
    /// Pad the hours in hh:mm and hh::mm:ss; pad the minutes in mm:ss
    LargestUnit,
}