Parameterize to allow side-by-side deploys

[MeltyBot]

Migrated from GitLab: https://gitlab.com/meltano/infra/terraform/-/issues/5

Originally created by @aaronsteers on 2022-02-15 23:27:51

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In several places where we are leveraging cloudposse modules, we have a namespace and stage reference which it would be good to parameterize - probably by accepting those two inputs or something similar explicitly as input variables to our module.

  # ...
  namespace = "m5o"
  stage     = "prod"
  name      = "meltano"

This would help with https://gitlab.com/meltano/squared/-/issues/48+