Allow a custom time provider in TracerProviderBase

[mikebosland]

This mirrors the capability in WebTracerProvider.

Which problem is this PR solving?

I have an opentelemetry implementation using the Dart library (thanks!). I've noticed clock skew between my web/flutter client and dart backend. I have clock synchronisation in the client. This PR allows me to provide my own TimeProvider which exposes synchronised time time, nicely aligning traces between app and server.

The WebTracerProvider constructor does allow providing a TimeProvider, but cannot be used in non-web platforms.

Fixes # 99 which is expanded in opentelemetry-js 1652

Short description of the change

Simply provide a named parameter to override the default TimeProvider in the TracerProviderBase, as is done in the WebTracerProvider.

How Has This Been Tested?

I have added a unit test demonstrating a custom time provider.

Checklist:

• Unit tests have been added
• Documentation has been updated
  • The README.md references a TimeProvider for WebTracerProvider. Should I update for TracerProviderBase?

[aviary2-wf]

Security Insights

No security relevant content was detected by automated scans.

Action Items

• Review PR for security impact; comment "security review required" if needed or unsure
• Verify aviary.yaml coverage of security relevant code

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[mikebosland]

This is my first pull request!

[mikebosland]

Thanks for the review!

This is my first proposal / use of github for code changes. Please let me know if there's something more I should be doing. :)

[blakeroberts-wk]

QA +1 CI is sufficient

[blakeroberts-wk]

@Workiva/release-management-p

[rmconsole-wf]

+1 from RM