Unify and streamline the `runTest.sh` commands

[oliverklee]

Story

As a developer, I want our runTests.sh commands to be as consistent as possible so that I can read them more easily and so that I can avoid problems related to differences.

As a developer, I want our runTests.sh command to be as similar as possible to the commands in the TYPO3 Core runTests.sh.

Acceptance criteria

• If there is a Core command for something, we use the Core's naming for it.
• Particular,y the cgl and phpCsFixer commands are merged.
• The naming of the commands is consistent (using lowerCamelCase).
• All commands that offer a dry-run option have it:
  • PHP-CS-Fixer
  • Rector
  • Composer-Normalize
• The help also uses the new names.
• The help and the commands are still sorted alphabetically.
• All commands that run PHP (or Composer) explicitly disable Xdebug.
• The schema for the container names (--name) is consistent.
• Only composer and the composer install/update commands provide the COMPOSER_CACHE_DIR environment variable.