s3:smbd: make sure we detect stale smbXsrv_connection pointers in smbXsrv_session_auth0

s3:smbd: make sure we detect stale smbXsrv_connection pointers in smbXsrv_session_auth0

Pointer values can be reused (yes, I hit that during my testing!).
Introduce a channel_id to identify connections and also add
some timestamps to make debugging easier.

This makes smbXsrv_session_find_auth() much more robust.

This is a similar change as 0cec96526bf4d3209caf36c4a19632ff5d5dd112:
 "smb2_server: make sure we detect stale smbXsrv_connection pointers in smbXsrv_channel_global"

BUG: https://bugzilla.samba.org/show_bug.cgi?id=11898

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Günther Deschner <gd@samba.org>