Add duration_unit option to Ecto plugin

[DaniruKun]

Change description

This change adds a new optional option to the Ecto plugin configuration - duration_unit.
It allows the user to override the time unit of the Ecto metrics, allowing to directly pass it through to :telemetry.

What problem does this solve?

Issue number: #139

Example usage

{Plugins.Ecto, [repos: [Shared.Repo], duration_unit: :second]}

Additional details and screenshots

Checklist

• I have added unit tests to cover my changes.
• I have added documentation to cover my changes.
• My changes have passed unit tests and have been tested E2E in an example project.

[akoutmos]

Thanks for the contribution! Would you mind also adding this to the other plugins for consistency?

[coveralls]

Coverage increased (+0.07%) to 79.686% when pulling d76e96d on DaniruKun:master into 9dbab16 on akoutmos:master.

[DaniruKun]

@akoutmos any update?

[akoutmos]

LGTM

[akoutmos]

Sorry for the delay on this one! Merging it in and cutting a new release soon :)