Add GCP Secret manager plugin

[D1StrX]

Please confirm the following

• [X] I agree to follow this project's code of conduct.
• [X] I have checked the current issues for duplicates.
• [X] 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

GCP Secret Manager provides similar service to Azure KeyVault. Not sure if the lookup plugin must be implemented for this. It would be great to see GCP Secret Manager supported as a Credential input source the same as Azure KeyVault.

Select the relevant components

• [ ] UI
• [X] API
• [ ] Docs
• [ ] Collection
• [ ] CLI
• [ ] Other

Steps to reproduce

.

Current results

Not available.

Sugested feature result

New credential type for GCP Secret Manager.

Additional information

No response

[jack-rep]

Lookup plugin was implemented here: https://github.com/ansible-collections/google.cloud/pull/578 So if that was a requirement, it is now satisfied. Want to see this added to AWX too!