ADMIN: Create separate issue templates for different use cases
I recall this being mentioned on one of the core dev calls a few months back, and took inspiration from [rapidsai/cudf](https://github.com/rapidsai/cudf) for the various templates.

Added templates for the following use cases:
- Bug Report
  - This is largely the same as the current issue template
- Documentation Enhancement
- Documentation Error
- Feature Request
- Submit Question
  - This attempts to direct users to StackOverflow for usage questions

We could also add a Blank Template for opening an issue without any template provided, but opted not to do that for now, as I don't want to encourage people to bypass these templates.  Could certainly add one if there's a consensus that we want this.

I've created a [local repo](https://github.com/jschendel/pandas-templates/issues) where you can see these templates in action since I couldn't figure out another way to actually display these.  Click the "New Issue" button to see what these changes would look like.

cc @pandas-dev/pandas-core @pandas-dev/pandas-triage 