Testsuite [WebDAV]: Fixed multiple testsuite bugs.
Encode the path in the Destination header in the same way as
the request path.
Censor any username and password from the Destination header URL.
Supply more locks for the MOVE, COPY and DELETE methods.
do_webdav_ls() now NFC-normalizes the expected paths.
Create missing directories in multiple tests.
The test_copy*_to_existing_*() tests now execute in unique
directories to avoid cross-pollution.
Fixed more issues with running on case sensitive filesystems.