feat: add "--no-index" option

[filipemarins]

Summary

Add --no-index option that allows disabling the index file generation.
This PR solves this issue.

Test plan

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[reintroducing]

@gregberge FYI this option in the API override does not seem to work, I had to add it to the CLI command I am running to disable the generation. I tried index: true and index: false and it had no impact and an index was still being generated. And also, the reason why I tried both is because its not immediately easy to figure out, due to the wording and the name of the option, to know which actually turns it off. I'd suggest renaming the API override to noIndex as well so that you know setting it to true disables index generation. index: true implies an index WILL be created.

[gregberge]

Hello @reintroducing you are right, I created an issue about it: #736