[TASK] Align with new TYPO3 documentation standards

[alexander-nitsche]

Hi Sebastian,

this PR is a suggestion to align your package documentation with the recently introduced TYPO3 documentation standards.

I mainly reworked some content, moved your documentation TOC to /docs, added some badges in README and additional sources (TER, repository and docs.typo3.org) in composer.json.

Greetings, Alex

Relates: TYPO3-Documentation/T3DocTeam#182
Relates: TYPO3-Documentation/T3DocTeam#185

[sabbelasichon]

@alexander-nitsche Thank you.
@helsner What do you think? You are the master of the documentation. Feel free to merge if you like.

[helsner]

thanks for your effort - looks good and i'm fine with all of that but one thing:
You removed the sentence where it says that this repo is only for dev and not to clone.
In the past we often had issues with people trying typo3-rector directly and not using rector/rector, so i would like to keep that somehow.
This won't prevent people 100%, but at least we can say it's in the docs :D
Whats you opinion on that @sabbelasichon ?

[alexander-nitsche]

Sure, adjust to your likes.

My explanation for the removal: I combined this hint with the mentioning of the parent Rector project:

It extends the Rector project, which aims to provide instant upgrades and instant refactoring for any PHP code (5.3+).

I would suggest to extend this sentence if you still want to be more precise on the Rector dependency here.

[helsner]

Ah ok, i'll think about something, but other than that thank you very much for your big change!

[sabbelasichon]

@alexander-nitsche @helsner Thanks both of you.