Improve credentials management

[zhenik]

Feature description

Improve credentials management in the example/standalone

1. (OPTIONAL) Not stored in the clean text in terraform state
2. (DEFAULT) User should be able to provide own credentials via config (terraform variables)
3. (OPTIONAL) User should be able to use existing creds from the vault (consul-template)

Q1. Can we have creds in output vars for the module with flag sensitive without breaking requirement #1? (NO)

• blocker #45
• blocker #66

Why is it needed?

Credentials management improvement improves security

Suggestion(s)/solution(s) [Optional]

Make a switch between user-provided credentials and creds which are managed by vault

Definition of done

User can provide own creds or use vault for creds management

Checklist (after created issue)

• Added label(s)
• Added to project
• Added to milestone