Extend WebDav option

[bramdejager]

Extend the WebDav option to open directly (currently implemented) and copy the WebDav URL (similarly like opening in other browsers)

Open WebDav from a folder. Currently a Folder only supports Refresh.

Open file in external editor (allow for external editor configuration). External editors like Notepad, and others. Opening file based on the WebDav URL as parameter to the editor.