Add Synthetics support

[dabcoder]

What does this PR do?

Adds support for Synthetics, follow up from #175 if we do not hear back from the contributor.

Description of the Change

No support existed for Synthetics within this client.

Alternate Designs

N/A

Possible Drawbacks

N/A - does not touch other features within this client.

Verification Process

• Integration tests
  Manually test the endpoints
• GET devices
• GET locations
• GET all tests
• GET info about a test
• GET most recent results about a test
• POST PUT start or pause test.
• GET a specific result
• POST create test
• PUT edit test
• POST delete tests

Release Notes

Add Synthetics support

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)
• PR must have one changelog/ label attached. If applicable it should have the backward-incompatible label attached.
• PR should not have do-not-merge/ label attached.
• If Applicable, issue must have kind/ and severity/ labels attached at least.

[gzussa]

This is great!
Let's double check tests are valid.
Also could we have integration tests as well.