GH: Convert feature request template to GH form
Mostly a 1:1 transfer. I removed the `API breaking implications` section though as the reviewers should have more/just-as-good insight into potential API impacts.
check if this displays ok Yup looks okay! https://github.com/pandas-dev/pandas/issues/new?assignees=&labels=Enhancement%2CNeeds+Triage&template=feature_request.yaml&title=ENH%3A+