mgr/cephadm: execute commands run over ssh via asyncssh

mgr/cephadm: execute commands run over ssh via asyncssh

_execute_command will run commands over ssh using the asyncssh `run` method: https://asyncssh.readthedocs.io/en/latest/api.html#asyncssh.SSHClientConnection.run
_check_execute_command will check the output of _execute_command and raise OrchestratorError if command fails on the remote host.
All commands run over ssh are prepended with sudo in `_execute_command` and shell-escaped with shlex quote.
If the cached ssh connection is closed or broken, the connection object will be removed from the cache, added to the `offline_hosts`, and an OrchestratorError will be raised. On the next call, the connection object will attempt to be recreated.
Exceptions involving asyncssh methods should be handled otherwise errors like TypeError: __init__() missing 1 required positional argument: 'reason' could occur due to the asyncssh error interacting with `raise_if_exception`

Fixes: https://tracker.ceph.com/issues/44676
Signed-off-by: Melissa Li <li.melissa.kun@gmail.com>