In SSHHook the timeout argument of the constructor is used to set a connection timeout. This is fine.

But in SSHOperator the timeout argument of the constructor is used for *both* the timeout of the SSHHook *and* the timeout of the command itself (see paramiko's ssh client exec_command use of the timeout parameter). This ambiguous use of the same parameter is very dirty.

I see two ways to clean the behaviour: 

1. Let the SSHHook constructor be the only way to handle the connection timeout (thus, if one wants a specific timeout they should explicitely build a hook to be passed to the operator using the operator's constructor).
2. Split the timeout argument in SSHOperator into two arguments conn_timeout and cmd_timeout for example.

The choice between 1 and 2 depends on how frequently people are supposed to want to change the connection timeout. If it is something very frequent. then go for 2. if not go for 1.

BR and thanks for the code!
airflow/providers/ssh/hooks/ssh.py
"""
        Creates appropriate paramiko key for given private key
        :param private_key: string containing private key
        :return: ``paramiko.PKey`` appropriate for given key
        :raises AirflowException: if key cannot be read
        """
        for pkey_class in self._pkey_loaders:
            try:
                key = pkey_class.from_private_key(StringIO(private_key), password=passphrase)
                
                
                key.sign_ssh_data(b'')
                return key
            except (paramiko.ssh_exception.SSHException, ValueError):
                continue
        raise AirflowException(
            'Private key provided cannot be read by paramiko.'
            'Ensure key provided is valid for one of the following'
            'key formats: RSA, DSS, ECDSA, or Ed25519'
        )