add optional WebDav propfind properties to show number of folders/files inside a folder
add optional WebDav propfind properties to show number of folders/files inside a folder

Signed-off-by: Julien Veyssier <8e8474783687c4f3f88ebb20cff5cefd8daba41d@posteo.net>

nextcloud/server,nextcloud/server,nextcloud/server,nextcloud/server