Fixes #37877 - Make the config file compatible with 0.2.z and 0.4.z

- broker is an array of mqtt servers used by 0.2
- server is an array of mqtt servers used by 0.4
- data-host needs to be set to an empty string to override certain compile-time
  defaults set in RHEL and CentOS Stream
- prefix needs to be set to the value we expect to override certain compile-time
  defaults set in RHEL and CentOS Stream

broker and server can be set at both once, each will be honored by their
respective versions

data-host and prefix can be set both at once on our build of yggdrasil they'll
just duplicate the defaults, on RHEL/CentOS Stream they'll act as overrides

app/views/unattended/provisioning_templates/registration/remote_execution_pull_setup.erb

@@ -54,10 +54,13 @@ if [ -f $CONFIGTOML ]; then
     cat <<EOF > $CONFIGTOML
 # yggdrasil global configuration settings written by katello-pull-transport-migrate
 broker = ["mqtts://$SERVER_NAME:1883"]
+server = ["mqtts://$SERVER_NAME:1883"]
 cert-file = "$CERT_FILE"
 key-file = "$KEY_FILE"
 ca-root = ["$CA_FILE"]
 log-level = "error"
+data-host = ""
+prefix = "yggdrasil"
 EOF
 
 else