This PR adds the Azure Monitor persistence provider, as requested in #454.

Description

Azure Monitor is the logging service by Microsoft. It allows configuring alerting based on events in logs, and also serves as the basis for Microsoft Sentinel, the cloud SIEM by Microsoft. As such, it can be desireable to push results from SCB into the system so that they can be acted upon.

This hook uses the data collector API to push the data into custom log types (one per scan type). For more details, read the included documentation.

At the moment, the code is fairly bare-bones and does not check if the data actually conforms to the expectations that Azure Monitor has, namely, a maximum of:

• 30 MB per POST request
• 32 KB per individual field value
• 50 characters per column name

The consequences for not respecting the field value and column name size limitations are truncation of the data. Too large POST requests will likely be rejected by the system with a HTTP error (not explicitly specified in docs). If desired, I can add more checks to the code to validate these requirements explicitly - I expect that 99.999% of secureCodeBox findings will fall within them without any extra modification. Truncation seems like an okay outcome to me (and cannot be prevented using checks on our end, since the only thing we could do is to truncate client-side). So the only place where we can actually do anything useful based on the client-side checks would be to split up POSTs that are larger than 30 MB into multiple individual POSTs. Do we expect findings to be larger than 30 MB?

Checklist

• Test your changes as thoroughly as possible before you commit them. Preferably, automate your test by unit/integration tests.
• Make sure npm test runs for the whole project.
• Make codeclimate checks happy