Add support for Synthetics Network tests

[melkouri]

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What does this PR do?

This PR adds support for Synthetics Network tests.
Used public API https://docs.datadoghq.com/api/latest/synthetics/#create-a-network-path-test

Description of the Change

Verification Process

Network tests successfuly replicated in R2 (see DDR org in US5) from R1 (US1 datadog2 org)

Additional Notes

Release Notes

Review checklist (to be filled by reviewers)

• Feature or bug fix MUST have appropriate tests (unit, integration, etc...)
• PR title must be written as a CHANGELOG entry (see why)
• Files changes must correspond to the primary purpose of the PR as described in the title (small unrelated changes should have their own PR)
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[melkouri]

This should be removed once the network test endpoint is fixed
ticket https://datadoghq.atlassian.net/browse/SYNTH-25321

[melkouri]

Fixed in Return monitor_id and monitor_priority to be an int instead of a string for Network Tests