Add --restricted_roles option to Monitors API

[pierreln-dd]

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What does this PR do?

This PR adds the "restricted_roles" argument to the Monitors API endpoint (see https://docs.datadoghq.com/api/latest/monitors/#create-a-monitor)

Description of the Change

Added the argument --restricted_roles to all the necessary parsers in order to be able to create/update/validate monitors with restricted roles

Alternate Designs

Possible Drawbacks

Verification Process

I installed the project locally and performed some local tests against my account. I specifically checked that I could add multiple roles, and checked in my DD account that the roles were properly added.
I also ran the tox integration tests but had a lot of errors that were not from my change.

Additional Notes

Release Notes

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• Feature or bug fix MUST have appropriate tests (unit, integration, etc...)
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