chore: Add templates for filing issues and submitting pull requests

[bryantbiggs]

Summary

Changes

• Add templates for filing issues and submitting pull requests. These are taken from https://github.com/awslabs/aws-lambda-powertools-python as a starting point, we can change to suit over time

User experience

• When users file issues, open feature requests, or submit PRs, they will now have a structured template that contains the information to help maintainers triage the request appropriately

Checklist

If your change doesn't seem to apply, please leave them unchecked.

• I have performed a self-review of this change
• Changes have been tested
• Changes are documented

Acknowledgment

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[mbeacom]

lgtm