We need to differentiate local_working_dir from working_dir
as well as decouple the stack user from `ansible_user` var.
Both of these are causing issues as we begin to automate
deployments in more environments.
- Cleanup duplicate variables that are consumed via extras-common
- Note: extras-common depends on the common role in OOOQ
- Cleanup redundant var and superfluous quotes from overcloud-scale
role
- Cleanup redundant comments in <role>/defaults/main.yml
Closes-bug: 1654574
Change-Id: I9c7a3166ed1fc5042c11e420223134ea912b45c5