Add issue and PR template for the ORAS repositories

[FeynmanZhou]

To make ORAS Pull Request and issue clear and traceable, I propose adding a Pull Request and issue template for the ORAS repositories.

Issue Template

Currently, I think these three types of issue template are enough for the ORAS community:

• Bug Report

- What happened in your environment?

- What did you expect to happen?

- How can we reproduce it (Please tell us your environment information as minimally and precisely as possible)?

- ORAS CLI version

- OS version

• Feature Request

- What would you like to be added?

- Why is this needed? Please describe your user story or scenario.

• Support

- What's your question?

- Environment: OS Information

- Error logs or messages (Attach logs or screenshots)

- ORAS CLI Version

PR Template

The PR template will include the following questions:

- What type of PR is this? 

- What this PR does / why we need it:

- Which issue(s) this PR fixes:

Fixes #

- Does this PR introduce a user-facing change? Is it necessary to update the documentation? 

- Additional documentation or context, e.g, Proposals, GitHub discussion, usage docs, etc.:

[vsoch]

@FeynmanZhou great idea! When we ask for specific information (e.g., versions) I would put in a bulleted list, like:

- **ORAS CLI version**:
- **What registry are you using?**:
- **OS Version**:

And rendered:

• ORAS CLI version:
• What registry are you using?:
• OS Version:

It's technically the same information, but in this form it (visually) seems like less than the large sections. And I removed the example registry names because I suspect people will be able to answer without it - we could add back if it seems like there isn't enough guidance for the question.

[FeynmanZhou]

@vsoch Okay. Thanks for your good suggestion! I intended to use this question as a survey, but I think I should remove the samples from the issue list.

[qweeah]

@FeynmanZhou Thanks for the effort. All templates look good and are exactly what we need.