Mjml: `options` are missing from documentation

[evenfrost]

Hi,
I've just faced the issue with missing mj-include file and noticed a bunch of similar issues, which pointed me to second options argument of mjml2html method found in source code. It would be great if a list with all available options was in Inside Node.js section. I believe it could help developers and reduce a number of related issues.

[iRyusa]

Hi !

I totally agree with you 👍
We'll see what we can do for the MJML4 release

[ngarnier]

Engine and CLI options are now documented in the readme so I'm closing!