Use ControlMaster where applicable. (Bug#13677)

Use ControlMaster where applicable.  (Bug#13677)

* net/tramp.el (tramp-ssh-controlmaster-template): New defvar,
replacing `tramp-detect-ssh-controlmaster'.
(tramp-default-method): Use it.

* net/tramp-sh.el (tramp-methods) [scp, scp1, scp2, scpx, sftp]:
[rsync, ssh, ssh1, ssh2, sshx]: Add ControlPath and ControlMaster
arguments.
[scpc, rsyncc]: Remove methods.
(top): Remove completion functions for "scpc", "rsyncc", "ssh1_old"
and "ssh2_old".
(tramp-do-copy-or-rename-file-out-of-band):  Change trace level.
(tramp-maybe-open-connection): Reuse tmpfile for ControlPath.