Time to update the Folder Structure

[Matt-PMCT]

Symfony 2 is long gone, and the Symfony folder structure has changed. I think it is about time that the main settings page has its language changed to match the supported versions of Symfony:

Even with no coding changes, if the text "App Directory" was changed to "Config Directory" and the "Web Directory" was changed to "Public Directory" it would better match all currently LTS versions of Symfony.

Clean up probably should involve the description of where the settings are. It currently says "File -> Settings -> Languages & Framework -> PHP -> Symfony" but in the newer versions of PhpStorm this has moved to "File -> Settings -> PHP -> Symfony".

I could do the pull, but wanted to see if this would be acceptable before I tried.