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/templates/virtual-mcp-ocata-dvr/underlay--user-data1604.yaml b/tcp_tests/templates/virtual-mcp-ocata-dvr/underlay--user-data1604.yaml
index 22b9d19..4d0ae3e 100644
--- a/tcp_tests/templates/virtual-mcp-ocata-dvr/underlay--user-data1604.yaml
+++ b/tcp_tests/templates/virtual-mcp-ocata-dvr/underlay--user-data1604.yaml
@@ -7,7 +7,9 @@
      sudo: ALL=(ALL) NOPASSWD:ALL
      shell: /bin/bash
      ssh_authorized_keys:
-      - ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDGwjUlYn9UsmWmAGSuEA2sICad7WqxgsJR0HKcMbbxi0tn96h4Cq2iGYmzlJ48egLm5R5pxyWnFvL4b/2zb+kKTPCMwRc9nv7xEGosEFNQEoSDd+gYu2CO0dgS2bX/7m2DXmzvhqPjxWQUXXsb0OYAS1r9Es65FE8y4rLaegz8V35xfH45bTCA0W8VSKh264XtGz12hacqsttE/UvyjJTZe+/XV+xJy3WAWxe8J/MuW1VqbqNewTmpTE/LJU8i6pG4msU6+wH99UvsGAOKQOduynUHKWG3VZg5YCjpbbV/t/pfW/vHB3b3jiifQmNhulyiG/CNnSQ5BahtV/7qPsYt vagrant@cfg01
+     {% for key in config.underlay.ssh_keys %}
+      - ssh-rsa {{ key['public'] }}
+     {% endfor %}
 
   disable_root: false
   chpasswd: