Establish Issue, Pull Request Templates

[bryanculver]

As a App maintainer, I would like a set standard Issue and Pull Request templates so that I can have features like:

• Automatically applied labels depending on Issue template choice (Feature vs Bug)
• Bug issues prompt for Nautobot, database, and app versions
• Pull requests provide a checklist and structure for quality submissions.

Core can be used as a reference for better default templates.

[smk4664]

There is already a pull_request_template.md in the baked Nautobot-app cookie, but Github is not using this. This might because it is in the wrong location or needs the name in CAPS.