Update SSH key management for Octavia

- Update Nova client metadta for Octavia to expect public key itself
  instead of path to it
- Pass private key contents to as metadata for Octavia manager

Relates to PROD-12506

Change-Id: Ie99d063e6bdc032757996e9201d8e08a69a2e0d3
diff --git a/octavia/manager/single.yml b/octavia/manager/single.yml
index a7bc7a9..acab136 100644
--- a/octavia/manager/single.yml
+++ b/octavia/manager/single.yml
@@ -5,3 +5,7 @@
     manager:
       enabled: true
       version: ${_param:octavia_version}
+      ssh:
+        private_key: ${_param:octavia_private_key}
+        user: octavia
+        group: octavia