refactor: Use `SystemTime` for timestamps

[dima74]

Context

Fixes #4729

Solution

Use std::time::SystemTime for time stamps instead of std::time::Duration.

• Note that SystemTime requires std, so it will not be available inside WASM.
• Alternatively chrono::DateTime might be used, but it will be more complex (in particular we will have to handle leap seconds), so I am not sure that it is worth it

Migration Guide (optional)

Review notes (optional)

Checklist

• [ ] I've read CONTRIBUTING.md.
• [ ] (optional) I've written unit tests for the code changes.
• [ ] All review comments have been resolved.

[0x009922]

From SDK standpoint, it can be useful to clearly see the separation between durations and timestamps in the schema. Currently they are just *_ms: u64 fields.

[dima74]

From SDK standpoint, it can be useful to clearly see the separation between durations and timestamps in the schema. Currently they are just *_ms: u64 fields.

One option I see here is to create DurationMs and TimestampMs newtype wrappers for u64 and use them correspondingly

[0x009922]

One option I see here is to create DurationMs and TimestampMs newtype wrappers for u64 and use them correspondingly

That would be helpful.