CI should auto-generate server_certs_key_passphrase

Bug 1833942 showed that in a case that the generated value
server_certs_key_passphrase is invalid, Octavia will fail to operate.

In CI, we currently provide a pre-defined passphrase that might cover
for potential breakages in the future. This patch removes the
pre-defined passphrase so it will get generated on each run.

Note that, TripleO will now[1] either auto-generate a valid passphrase
or validate a pre-defined one.

Related-Bug: #1833942

[1] https://review.opendev.org/#/q/topic:OctaviaServerCertsKeyPassphrase-32chars

Depends-On: I5c2629d9e7700fe1dd6f915bc257b1f058e40617
Depends-On: Ibcdbe2605a7cabe3a5ef8245b4460c8f70220989
Depends-On: I886f2b8ac7092d9b3da38852e92a615d5666eea7

Change-Id: Ie596b04614c2ca9d961694f4012c1553a092aa3e

ci/environments/scenario010-multinode-containers.yaml

@@ -112,7 +112,6 @@ parameter_defaults:
   NeutronEnableForceMetadata: true
   OctaviaManageNovaFlavor: true
   # For now, we hardcode it but soon it'll be generated in tripleo-common
-  OctaviaServerCertsKeyPassphrase: 'insecure-key-do-not-use-this-key'
   OctaviaCaKeyPassphrase: 'upstreamci'
   OctaviaGenerateCerts: true
   # Remove ContainerCli once this scenario is tested on CentOS8

ci/environments/scenario010-standalone.yaml

@@ -32,7 +32,6 @@ resource_registry:
 
 parameter_defaults:
   OctaviaAmphoraSshKeyFile: /home/zuul/.ssh/id_rsa.pub
-  OctaviaServerCertsKeyPassphrase: 'insecure-key-do-not-use-this-key'
   NodeDataLookup:
     AB4114B1-9C9D-409A-BEFB-D88C151BF2C3: {"foo": "bar"}
     8CF1A7EA-7B4B-4433-AC83-17675514B1B8: {"foo2": "bar2"}