doc(cli): document viz.js warning on node 12

[sverweij]

Description

• in the readme document the occurrence of a warning message on the command line
• add a faq document
• in the cli do the same (conditionally, only when relevant; when node version >= 12)

Motivation and Context

• fixes Broken dependency viz.js – "Invalid asm.js: Function definition doesn't match use" #82

How Has This Been Tested?

• README: by applying eye balls
• cli: additional unit test(s)

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• The code I add will be subject to The MIT license, and I'm OK with that.
• The code I've added is my own original work.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[codeclimate]

Code Climate has analyzed commit 3d43a9f and detected 0 issues on this pull request.

The test coverage on the diff in this pull request is 100.0% (100% is the threshold).

This pull request will bring the total coverage in the repository to 100.0% (0.0% change).

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