On demand test

[aaronfay]

Adds on-demand test execution, and some cleanup. It took me a bit to figure out where the API key to run the integration tests comes from, I've updated the docs to be more specific about how to test things.

Specific changes:

• adds unit tests for the client methods
• moves existing tests to test/integration
• adds method executeTestOnDemand()
• adds method importTest()
• adds methods waitForTestResult() and waitForSuiteResult() (which implement polling)
• converts executeTest() and executeSuite() to use ☝️above polling methods by default
• some general cleanup + docs

@justinklemm it's not clear to me if you provide a CSV for executeTest() and specify immediate=true, is there a way to poll for these results as a whole? Or would we need to check each result individually?

PS: I've added the API key to run the integration tests into our vault. PPS: not sure what's up with CircleCI, digging into that next.

[aaronfay]

@justinklemm I'm blocked on a couple things here:

• The execute test on-demand integration test won't pass until this PR is closed
• I couldn't find any information on how to log into the api@ghostinspector.com account, I'd like to add a specific suite for an importTest() integration test at some point.

[aaronfay]

@simpixelated (and @justinklemm ) thanks for the feedback, I realized I was missing a couple tests for waitForTestResult and waitForSuiteResult and with your feedback I think the implementation is much cleaner. Latest changes in https://github.com/ghost-inspector/node-ghost-inspector/pull/9/commits/1ae23ce15425b714c853da21fa03f49b14dcade3

[aaronfay]

@justinklemm the version is bumped to 4.1.0, please release at your convenience 🙏