Improve time label

[blairlyons]

• [ ] https://github.com/simularium/simularium-website/issues/318
• [ ] https://github.com/simularium/simularium-website/issues/176
• [ ] https://github.com/simularium/simularium-planning/issues/37

Use case

As a user, I want the time label to be easy to read even if decimal points change or if minutes or hours are used as units.

Acceptance Criteria

• Decimal values in time label stay consistent during playback
• Hour and minutes are displayed using common conventions

[lynwilhelm]

Add more decimal points to this ticket as a work item