oss developer experience: PULL_REQUEST_TEMPLATE.md and ISSUE_TEMPLATE.md missing

[ghuntley]

Howdy Wire.

This repository does not have a PULL_REQUEST_TEMPLATE.md and ISSUE_TEMPLATE.md

See below for examples:

• https://github.com/reactiveui/ReactiveUI/blob/develop/.github/PULL_REQUEST_TEMPLATE.md
• https://github.com/reactiveui/ReactiveUI/blob/develop/.github/ISSUE_TEMPLATE.md

Refer to https://github.com/flexyford/pull-request-template for more insights as to why these are needed.