Add support for seconds

[LukasAnda]

Hey, thanks for porting this library to compose multiplatform! I was wondering, I'm making a stopwatch/timer app, would it be possible to have seconds in the spinner as well? Or could I somehow even help implementing that?

[darkokoa]

Hi, I'm happy to add this feature. Do you think about how it should be implemented? 🤔

Here are 3 things to consider:

1. Should seconds be optional, or required by default?
2. How will the time picker's / datetime picker's width be affected by adding seconds?
3. Should the padding between elements in the time picker / datetime picker be reduced to accommodate adding seconds?

[LukasAnda]

Hey I'm sorry for taking so long to get back to you.

1. I think it should be passed as an argument (maybe based on the format, so I can choose even to display Hours:seconds or minutes:seconds for whatever reason)
2. Well it should wrap the width anyway no?
3. Hmm maybe provide a modifier/ContentPadding to be able to change this during runtime?

[darkokoa]

OK. For now the picker can not set date and time formats, I will temporarily use HH:MM:SS for the time format.

[LukasAnda]

Sure, that works for me as well