Handling of SSH Protocol Banner timeout in PyEZ

[chidanandpujar]

Handling of SSH Protocol Banner timeout in PyEZ

banner_timeout value has fixed value of 15 seconds as per paramiko, we will check if there is any option from paramik to change the default values .
              [paramiko/paramiko/transport.py at main · paramiko/paramiko (github.com)](https://github.com/paramiko/paramiko/blob/main/paramiko/transport.py#L517)
 
# how long (seconds) to wait for the SSH banner
                 self.banner_timeout = 15

[apurvaraghu]

As per the current version of Paramiko, we can pass 'banner_timeout' variable with required value while calling the connect method.

An example for the same is as below:

client = SSHClient()
client.connect('ssh.example.com', banner_timeout=200)

Totally there are 3 options available for timeout:
• banner_timeout - an optional timeout (in seconds) to wait for the SSH banner to be presented.
• timeout - an optional timeout (in seconds) for the TCP connect
• auth_timeout - an optional timeout (in seconds) to wait for an authentication response.

Link that references to these parameters in the paramiko cllient.py code:
https://github.com/paramiko/paramiko/blob/51eb55debf2ebfe56f38378005439a029a48225f/paramiko/client.py#L225-L235

[chidanandpujar]

ncclient manger.connect method does not support the option to pass banner_timeout .

(Pdb) 
TypeError: connect() got an unexpected keyword argument 'banner_timeout'
> /root/pyez_release_272_py39/venv/lib/python3.9/site-packages/ncclient-0.6.15-py3.9.egg/ncclient/manager.py(187)connect()
-> return connect_ssh(*args, **kwds)
(Pdb) 
--Return--
> /root/pyez_release_272_py39/venv/lib/python3.9/site-packages/ncclient-0.6.15-py3.9.egg/ncclient/manager.py(187)connect()->None
-> return connect_ssh(*args, **kwds)
(Pdb) 
TypeError: connect() got an unexpected keyword argument 'banner_timeout'
> /root/pyez_release_272_py39/venv/lib/python3.9/site-packages/junos_eznc-2.7.1+9.ga64698b2.dirty-py3.9.egg/jnpr/junos/device.py(1376)open()
-> self._conn = netconf_ssh.connect(
(Pdb) 
> /root/pyez_release_272_py39/venv/lib/python3.9/site-packages/junos_eznc-2.7.1+9.ga64698b2.dirty-py3.9.egg/jnpr/junos/device.py(1396)open()
-> except NcErrors.AuthenticationError as err:

as of now, paramiko SSHClient() supports the banner_timeout .
paramiko.SSHClient() is used only in start_shell and scp modules, we will check whether we can support banner_timeout for these modules.