[FEATURE] Rst File Exporter

[maddy2101]

This exporter creates rst file in the form the official TYPO3 documentation requires.

It will skip all version related details.

[maddy2101]

I am not sure how to deal with the badges in the readme, as those currently point to my accounts. Please feel free to adjust as you see fit.

[NamelessCoder]

The quality of this work is really impressive, I did not expect you to go all-in and add CI and tests! That's super appreciated. I am however hesitant to integrate a separate format - had it not been for the absolutely minimal footprint of the JSON format export I probably wouldn't have added that either but would instead have made it a separate package (I may still do that as a way to eat my own dog food given what I'm about to suggest).

I think we can look at this as three separate things:

1. The metadata parts - I'm in full agreement here and if you like, I can extract those changes so you don't have to bother with it.
2. The change to API of the engine - the addition of force flag on root export method. Also in agreement, I have no objections, but should be a separate feature we can clearly mark as breaking (not that I expect anyone has created integrations yet, except for this one here).
3. The RST exporter itself - which I would very much prefer as a separate package. I volunteer to take care of the maintenance if you prefer it just gets put here on my account, and will definitely make this package use it in suggest regardless where it gets created.

Also referring to my comment on #5 (comment) about a better CLI tool for invoking the generator.

Lastly I hope this doesn't diminish the effort you put into this. I will of course assist with the further work and creation of new package(s). So I guess the bigger questions are if you agree with this suggested packaging strategy and if so, where do we put what?