Twig CS Fixer tool for Contrib projects

Now that Core has adopted the twig-cs-fixer package to check for Twig coding standards, the Gitlab Templates project has been working on the equivalent feature for Contrib. It is now tested and ready, but wont become available to all until core 11.5 is released.

The initial work was done here and further enhancements done here.

We wanted to make contact with the Coding Standards teams so that (a) you are aware of what is happening and (b) we can co-ordinate/decide/prepare an announcement to make.