Enhance docs for xray

[joe4dev]

Changes

• Update the X-Ray docs with the new template.
• Completely re-write the docs: Add a new generic X-Ray tutorial section instead of the Lambda-related snippet.
• Link to the new lambda-xray pro samples in Add new Lambda X-Ray samples localstack-samples/localstack-pro-samples#226

Preview

https://localstack-docs-preview-pr-823.surge.sh/user-guide/aws/xray/

TODO

• Write short tutorial
• Create new Pro sample. My messy example in this PR based on the aws-lambda-developer-guide blank-python sample needs quite some cleanup. Instead of using the X-Ray SDK, OpenTelemetry or PowerTools could be good instrumentation alternatives as mentioned in the AWS docs: https://docs.aws.amazon.com/lambda/latest/dg/python-tracing.html
• Link to new Pro sample

[github-actions]

🎊 PR Preview has been successfully built and deployed to https://localstack-docs-preview-pr-823.surge.sh 🎊

[joe4dev]

sidenote: If we decide to improve our X-Ray support in the future, the docs should add some visual overview to explain this complex topic.