doc: Add issue templates for example and test, and update the contribution guidelines and PR templates with corresponding examples

[kurosakishigure]

Description

• Add issue templates for example and test, and update the contribution guidelines and PR templates with corresponding examples
• What is the purpose of this PR?
  • See Add the "test" and "example" tags #90
• What problem does it solve?
  • See Add the "test" and "example" tags #90
• Are there any breaking changes or backwards compatibility issues?
  • None

Related Issue

• Closes Add the "test" and "example" tags #90

Type of Change

• Documentation update

How Has This Been Tested?

• I have run unit tests
• I have tested the changes manually
• I have tested in a staging environment

Checklist

• My code follows the coding style guidelines of this project
• I have written or updated relevant documentation (if applicable)
• I have added or updated tests to cover my changes (if applicable)
• All new and existing tests pass
• I have reviewed my code for any potential issues
• Link the relevant issue to this PR (if applicable)
• Add labels to this PR
• I have read and followed the guidelines in CONTRIBUTING.md

Additional Notes

None.

[github-actions]

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