Allow disabling server certificate verification on https protocol.

If https protocol is used but server does not have a verified certificate, requests shall be fail with the following error -

requests.exceptions.SSLError: [Errno 1] _ssl.c:504: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed

To resolve this I add option to control the request verify argument and allow to disable certificate verification by using -

rd = Rundeck(server='localhost', protocol='https', port=4443, api_token="xxxx", verify_cert=False)