Many rules were disabled to prevent numerous code formatting changes during the GWT->React refactoring. Now's the time to get rid of these exception and align code style with Vehicle Routing.

Basically get rid of all of these disabled rules: https://github.com/kiegroup/optaweb-employee-rostering/pull/271/files#diff-d7b1c97d61e88c262e611d2cf7aed1a5.

Please do not mix the code style alignment with new features development. Feel free to even divide this task into multiple PRs, each enabling a subset of the disabled rules. Since some of the rules can be fixed automatically and the result is basically guaranteed by the ESLint check it's not necessary to review these PRs thoroughly so a single huge PR would be OK as well as long as it only contains code style changes.