And use correct encoding when printing to files.

The following new functions are added to ct_netconfc:

* connect/1,2 - open an SSH connection to a netconf server
* disconnect/1 - close the given SSH connectoin
* session/1,2,3 - open an SSH channel on the give connection and send
  'hello' to start a netconf session.

This allows running multiple channels on on SSH connection, realizing
one netconf session per channel. The existing ct_netconfc:open will
always run one channel(session) per SSH connection.

If setting the value for this option to an integer, N, common_test
will remove all ct_run.* directories in the current log directory,
except the N newest.

The default value for the 'keep_logs' option is 'all', which means that
no logs will be deleted.

'keep_logs' can be used in combination with refresh_logs, or in a normal
common_test test run.

* siri/ct_hooks/callbacks-on-skip/OTP-10599:
  [ct] Update built-in ct hooks with new Suite parameter
  [cth_surefire] Handle skips from test spec
  [ct] Remove excessive skipped/failed tag in hook function
  [ct] Send tc_start event on force_stop and failed sequence
  [ct] Correctly handle process died in init and end_per_testcase
  [ct] Fix faulty hook callbacks for skipped tests
  Add dummy end_per_suite/1
  [ct] Fix hooks and fail when one of init/end_per_* does not exit
  [ct] Add Suite argument to hook callback functions
  [ct] Fix function_clause in ct_framework when hook function crashes

* siri/ct/get_dirs_from_testspec/OTP-14132:
  [ct] Add ct_testspec:get_tests/1