Add a metrics library to artemislib

[Kamsiy]

Description

Adds a metrics library to artemislib and adds a custom metrics provider class for datadog

Motivation and Context

How Has This Been Tested?

tested in a dev environment

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation change

Checklist

• My code follows conforms to the coding standards.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

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