Include minimum permissions to run Kong without root

### Where is the problem?

https://docs.konghq.com/gateway/latest/production/running-kong/kong-user/

### What happened?

We should furnish out the minimum permissions to run Kong without root instead of a note which is not conclusive. It is a common security concern for any tools to be run in a production environment.

### What did you expect to happen?

List out the minimum permissions to run Kong with the kong user and group

### Code of Conduct and Community Expectations

- [X] I agree to follow this project's Code of Conduct
- [X] I agree to abide by the Community Expectations

Start with the Kong user documentation page linked in the issue. Determine the minimum permissions required for the kong user and group to run Kong without root, then update that page so the permissions are explicitly listed and conclusive.

Written by the indexing model from the issue text.