Remove non-routes from route:list

[galdiuz]

Current Implementation

The route:list command currently uses \Magento\Framework\Module\Dir\Reader->getActionFiles() to find classes in every module's Controller directory. However, all of these classes don't actually represent an actual route, as there can be things like abstract classes, interfaces, or just plain non-action classes.

Suggested Enhancement

Check each class before including it. This can be done at the start of the foreach in ListCommand.php. Using is_a($fullActionPath, '\Magento\Framework\App\ActionInterface', true) to check if the class implements ActionInterface would catch all non-action classes, then reflection could be used to also catch any abstract classes.

Expected Benefits

route:list would no longer list results that are not accessible paths.

[cmuench]

Will be released with v7.3.0