Suggest CI/CD workflows for iOS & Android customers

Currently, the `.gitignore` generated by the Amplify CLI intentionally excludes `awsconfiguration.json` and `amplifyconfiguration.json` files, by design. This is done so that users _opt-in_ to committing these files. Depending on what has been configured, and the security posture of the customer's application, these files may contain information that is **not** suitable to store on disk in a repo.

However, where _should_ the customer put them, then? And how does the application under test access them, so that tests can be invoked?

These questions arise for customers building out production CI/CD pipelines. The Amplify documentation should include guidance on who to securely store, access, and bundle configurations in a popular CI/CD runtime.

Reference: https://github.com/aws-amplify/amplify-android/discussions/1005#discussioncomment-140264