TdjDefaultWebComponent : check if the context docroot folder exists

[michaelJustin]

From PDF:

For every context, the framework can provide a folder for static resources (images, scripts, style sheets or static HTML documents). ... TdjDefaultWebComponent serves resources which do not match the URL mapping of any other web component, and tries to serve them from the static resource folder.

The static resource folder is located under the webapps directory of the server and has the same name as the context.