docs: describe how to set up properly

a note in the docs where the default dav port is, how to connect and where to pass the SID would be nice e.g. dav://MY_SID:egal@localhost:8080 with MY_SID from https://textgridlab.org/1.0/Shibboleth.sso/Login?target=/1.0/secure/TextGrid-WebAuth.php?authZinstance=textgrid-esx2.gwdg.de