[DOCS] Add terraform inventory source to Inventories chapter of Userguide

[tvo318]

Please confirm the following

• I agree to follow this project's code of conduct.
• I have checked the current issues for duplicates.
• I understand that AWX is open source software provided for free and that I might not receive a timely response.

Feature type

New Feature

Feature Summary

Reference PR #14840 to add Terraform to https://ansible.readthedocs.io/projects/awx/en/latest/userguide/inventories.html#inventory-sources

Select the relevant components

• UI
• API
• Docs
• Collection
• CLI
• Other

Steps to reproduce

See instructions in https://ansible.readthedocs.io/projects/awx/en/latest/userguide/inventories.html#inventory-sources

Current results

Missing Terraform Inventory Source

Suggested feature result

Terraform inventory source added to docs

Additional information

(https://docs.google.com/document/d/1a2Z8SceITxL8gCPUt6Uo3SFkrMupunCFYiutq8s0JtU/edit#heading=h.hrc43got0pg5)

[nerijus]

Additional information URL is asking for access - could it be made public?

[tvo318]

@nerijus - Hi, I don't understand your question. Can you elaborate?

[nerijus]

I mean https://docs.google.com/document/d/1a2Z8SceITxL8gCPUt6Uo3SFkrMupunCFYiutq8s0JtU/edit#heading=h.hrc43got0pg5 is asking:

[tvo318]

@nerijus - I'm not the author of that doc, I believe that draft is internal. It's best to take a look at the PR itself for the rendered content on terraform: #15004

[tvo318]

See final content here:

• Credentials: https://ansible.readthedocs.io/projects/awx/en/latest/userguide/credentials.html#terraform-backend-configuration
• Inventories: https://ansible.readthedocs.io/projects/awx/en/latest/userguide/inventories.html#terraform-state