Modifies the `analytics_single.yml` playbook to be able to use it to set up single-VM production analytics servers.
*JIRA tickets*: OSPR
*Sandbox URL*: TBD - sandbox is being provisioned.
*Merge deadline*: "None"
[ ] @gr4scale
[ ] edX reviewer[s] TBD
Configuration Pull Request
Make sure that the following steps are done before merging:
[ ] A DevOps team member has approved the PR if it is code shared across multiple services and you don't own all of the services.
[x] Are you adding any new default values that need to be overridden when this change goes live? No
[ ] If you are making a complicated change, have you performed the proper testing specified on the [Ops Ansible Testing Checklist](https://openedx.atlassian.net/wiki/display/EdxOps/Ops+Ansible+Testing+Checklist)? Adding a new variable does not require the full list (although testing on a sandbox is a great idea to ensure it links with your downstream code changes).
[ ] Think about how this change will affect Open edX operators. Have you updated the wiki page for the next Open edX release?