Add Issue-template and fix prow workflow

[seokho-son]

This PR proposes

• Add GitHub Issue templates
• Fix GitHub workflow for action by command-style comments (inspired by Kubernetes Prow))

Supported comments are as follows, /assign /unassign /approve /retitle /area /kind /priority /remove /lgtm /close /reopen /lock /milestone /hold /cc /uncc

This GitHub workflow is based on jpmcb/prow-github-actions . https://github.com/jpmcb/prow-github-actions/blob/main/docs/commands.md

You can see a demo PR from https://github.com/seokho-son/docs/pull/18 to check actions.

[sykim-etri]

/lgtm

[sykim-etri]

/approve