[#120] improvement(github): add issues and PR template (#121)

### What changes were proposed in this pull request?

As title

### Why are the changes needed?

Make management easier.

Fix: #120

### Does this PR introduce _any_ user-facing change?

No

### How was this patch tested?

Copy from Gravitino, it's work at Gravitino.

.github/ISSUE_TEMPLATE/bug-report.yml

@@ -0,0 +1,48 @@
+name: Bug Report
+title: "[Bug report] "
+description: A bug report issue
+labels: [ "bug" ]
+body:
+
+  - type: dropdown
+    id: version
+    attributes:
+      label: Version
+      description: What version are you running?
+      options:
+        - main branch
+      default: 0
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Describe what's wrong
+      description: >
+        A clear and concise description of what works not as it is supposed to.
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Error message and/or stacktrace
+      description: >
+        If applicable, add screenshots to help explain your problem.
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: How to reproduce
+      placeholder: >
+        + Which version to use
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Additional context
+      placeholder: >
+        Any other context about the problem here.
+    validations:
+      required: false

.github/ISSUE_TEMPLATE/epic.yml

@@ -0,0 +1,31 @@
+name: Epic
+title: "[EPIC] "
+description: An epic issue with multiple sub-tasks
+labels: [ "epic" ]
+body:
+
+  - type: textarea
+    attributes:
+      label: Describe the proposal
+      description: >
+        Please put the related docs here if required.
+      placeholder: >
+        Please describe the content of the proposal clearly and concisely.
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Task list
+      description: >
+        For more details, please refer to [github docs](https://docs.github.com/en/issues/tracking-your-work-with-issues/about-task-lists).
+      placeholder: >
+        Please create sub-tasks with the pre-create issues here and @ the assignees if you know any of them. A simple example is as follows:
+          - [ ] #1
+            - [ ] #11 @user1
+            - [ ] #12
+            - [ ] #13
+          - [ ] #2 @user2
+          - [ ] #3
+    validations:
+      required: true

.github/ISSUE_TEMPLATE/feature-request.yml

@@ -0,0 +1,40 @@
+name: Feature Request
+title: "[FEATURE] "
+description: Suggest an idea
+labels: [ "feature" ]
+body:
+
+  - type: textarea
+    attributes:
+      label: Describe the feature
+      description: What is it?
+      placeholder: >
+        Please describe the feature you want here.
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Motivation
+      description: Why should it be implemented?
+      placeholder: >
+        Please describe your motivation for requesting this feature.
+    validations:
+      required: false
+
+  - type: textarea
+    attributes:
+      label: Describe the solution
+      description: How could it be implemented?
+      placeholder: >
+        Please describe the solution to implement the new feature if you have any.
+    validations:
+      required: false
+
+  - type: textarea
+    attributes:
+      label: Additional context
+      placeholder: >
+        Anything else we need to know.
+    validations:
+      required: false

.github/ISSUE_TEMPLATE/improvement.yml

@@ -0,0 +1,21 @@
+name: Improvement
+title: "[Improvement] "
+description: Suggest an improvement on performance, code quality, user experience, etc
+labels: [ "improvement" ]
+body:
+
+  - type: textarea
+    attributes:
+      label: What would you like to be improved?
+      placeholder: >
+        Please describe the problem you see and how it is needed to be improved.
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: How should we improve?
+      placeholder: >
+        Please provide the solution if you have thoughts.
+    validations:
+      required: false

.github/ISSUE_TEMPLATE/subtask.yml

@@ -0,0 +1,21 @@
+name: Subtask
+title: "[Subtask] "
+description: A subtask issue
+labels: [ "subtask" ]
+body:
+
+  - type: textarea
+    attributes:
+      label: Describe the subtask
+      placeholder: >
+        Please describe the content of the subtask clearly and concisely.
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Parent issue
+      placeholder: >
+        Please put the parent issue link here.
+    validations:
+      required: true

.github/PULL_REQUEST_TEMPLATE

@@ -0,0 +1,35 @@
+<!--
+1. Title: [#<issue>] <type>(<scope>): <subject>
+   Examples:
+     - "[#123] feat(operator): support xxx"
+     - "[#233] fix: check null before access result in xxx"
+     - "[MINOR] refactor: fix typo in variable name"
+     - "[MINOR] docs: fix typo in README"
+     - "[#255] test: fix flaky test NameOfTheTest"
+   Reference: https://www.conventionalcommits.org/en/v1.0.0/
+2. If the PR is unfinished, please mark this PR as draft.
+-->
+
+### What changes were proposed in this pull request?
+
+(Please outline the changes and how this PR fixes the issue.)
+
+### Why are the changes needed?
+
+(Please clarify why the changes are needed. For instance,
+  1. If you propose a new API, clarify the use case for a new API.
+  2. If you fix a bug, describe the bug.)
+
+Fix: #(issue)
+
+### Does this PR introduce _any_ user-facing change?
+
+(Please list the user-facing changes introduced by your change, including
+  1. Change in user-facing APIs.
+  2. Addition or removal of property keys.)
+
+### How was this patch tested?
+
+(Please test your changes, and provide instructions on how to test it:
+  1. If you add a feature or fix a bug, add a test to cover your changes.
+  2. If you fix a flaky test, repeat it for many times to prove it works.)