Rector: added dependency and basic rules

[sreichel]

Description (*)

• added rector as composer dependeny
• added rules to config (all these rules have already been used ... nothing new here at all)
• fixed a few lines (maybe new, or newly dedected)
• added rector to workflow
• added ddev & composer shortcuts

ddev:

ddev rector --dry-run

ddev rector

composer:

composer run rector:test

composer run rector:fix

... add a path to this commands to test your own extensions code.

Happy coding :)