Node keep can be wrongly installed without creating the alias_keeper field

Added a MR with the first approach: Add dependency on pathauto.

Based on https://www.drupal.org/project/node_keep/issues/3361172#comment-15056012 🐛 Node keep can be wrongly installed without creating the alias_keeper field Needs work from @akalam I created a patch following the approach: Add dependency on pathauto.

Patch partially did not apply. Something with the last line and *.info.yml adding extra lines when performing composer install.

Fixed coding standards, updated README

Pathauto should stay an optional dependency. Otherwise, that part of the functionality should be extracted into a submodule. The module shouldn't require to install pathauto.

ant1 → changed the visibility of the branch 3361172-node-keep-can to hidden.

I created a initial setup for the submodule.
There is still the issue of data loss regarding this setting with the upgrade.