[Standalone Upgrade] Use output directory same as deploy

Standalone deploy already switched to <working_dir>/tripleo-deploy
in [1], for same reasons switch the standalone upgrade too.

Also when using different output directory, passwords
get's regenerated during upgrade and causing issues
like #1935691.

[1] https://review.opendev.org/c/openstack/tripleo-quickstart-extras/+/789764

Closes-Bug: #1935691
Change-Id: If6c1892d9f3d4613163dca2a0f7f293bf076a7b6

roles/standalone-upgrade/templates/standalone.sh.j2

@@ -16,5 +16,5 @@ sudo openstack tripleo upgrade $PROMPT_ANSWER \
 {% if standalone_custom_env_files %}
   -e {{ standalone_custom_env_files | join(' -e ') }} \
 {% endif %}
-  --output-dir {{ working_dir }} \
+  --output-dir {{ working_dir }}/tripleo-deploy \
   --standalone