Add new command to generate test files for actions

[michaelklopf]

We used DomainGeneratorCommand as a blueprint for the test creation. DTO command will come next.

Allows to create tests for actions with an artisan command. Makes it easier to create test cases at the correct location to increase consistency in test creation.

We recommend to create further test methods with a VSCode snippet. You can add user snippets for php files when searching for snippets in the preferences.

  "Test Method": {
    "prefix": "test",
    "body": ["/** @test */", "public function $1()", "{", " $3", "}"]
  },

Sorry, I branched from the master that has the config changes.