Diagnostic Center

EDIT: Phase 1 is complete and rolled out publicly as the `ASSERTION` command. This issue is now solely for Phase 2 (the diagnostic center).

Add a `TEST` command allowing the sequence builder to function as a test-making tool, and the CSVM as the test runner.

[Mockup.pdf](https://github.com/FarmBot/Farmbot-Web-App/files/3518794/Test.Command.%2B.Diagnostic.Center.pdf)

### Use cases/needs
* Automate much of the process of testing FBOS and firmware release candidates
* Automate long-term, high-cycle hardware testing
* Diagnostic tooling to help users diagnose hardware issues
* Allow users greater ability to ensure reliable operation of their FarmBot

### Initial implementation
Will be an internal-only tool initially. The plain-text assertion field will get parsed by FBOS's Lua interpreter, allowing simple to complex evaluations of most(?) things in FBOS's state tree. Test result logs should be sent with a new type, `test`, which can initially be filtered for in the normal logs page.

### Phase two
Public release of the command along with a dedicated diagnostics page specific for showing test results. Consider adding a more user-friendly method of defining assertions based on dropdowns and validated input fields. Devise a way to give users access to FarmBot Inc made and maintained bot-specific test suites that can be used to diagnose hardware issues.