Add option to get queueURL from env for aws SQS scaler

[fk128]

Add queueURLFromEnv as additional trigger metadata to allow loading the queueURL from env variables.

It would be useful to be able to set the queueURL to load from env variables, especially when having multiple deployment environment. This way if using kustomize, the queueURL could be defined in a configmap and loaded as env variable, rather than patching the manifest. This for example would be similar to the addressFromEnv in the redis-lists scaler.

Signed-off-by: Fahdi Kanavati [email protected]

Provide a description of what has been changed

Checklist

• [x] Commits are signed with Developer Certificate of Origin (DCO - learn more)
• [x] Tests have been added
• [x] A PR is opened to update the documentation on (repo) (if applicable)
• [ ] Changelog has been updated and is aligned with our changelog requirements

Fixes #

Relates to # https://github.com/kedacore/keda-docs/pull/902