Use generated RSA key while accessing nodes via SSH

Generate RSA key pair (optionally it could be provided by
operator via environment variable) and use it for SSH
authentication instead of password.

Also it's possible to provide the key from a local file now.

Change-Id: I5fea4d55337f294cd7829392b91b2cca7b85ead5
Reviewed-on: https://review.gerrithub.io/367254
Reviewed-by: Victor Ryzhenkin <vryzhenkin@mirantis.com>
Reviewed-by: Dennis Dmitriev <dis.xcom@gmail.com>
Tested-by: Dennis Dmitriev <dis.xcom@gmail.com>
diff --git a/tcp_tests/settings_oslo.py b/tcp_tests/settings_oslo.py
index d761d7f..ca0aef2 100644
--- a/tcp_tests/settings_oslo.py
+++ b/tcp_tests/settings_oslo.py
@@ -98,6 +98,11 @@
                    tests or during the deployment process.
                    {'pool_name1': '<cidr>', 'pool_name2': '<cidr>', ...}""",
            default={}),
+    ct.Cfg('ssh_keys', ct.JSONList(), default=[],
+           help="SSH key pair(s) for root. If the option is left empty, "
+                "then a key pair will be generated automatically"),
+    ct.Cfg('ssh_key_file', ct.String(), default=os.path.abspath('./id_rsa'),
+           help='Path (local) to file with private key authorized on nodes'),
 ]