Add PR/Issue template and actions to validate PR status.

[jiajunwang]

Issues

• My PR addresses the following Helix issues and references them in the PR description:

Resolves #1222

Description

• Here are some details about my PR, including screenshots of any UI changes:

Add 2 issue templates and one PR template to the Helix project.
Also, add Github actions based on the PR template so as to automatically update the PR status based on any PR updates.

Tests

• The following tests are written for this issue:

Tested in my forked repo, jiajunwang#8

• The following is the result of the "mvn test" command on the appropriate module:

NA

Commits

• My commits all reference appropriate Apache Helix GitHub issues in their subject lines. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters (not including Jira issue reference)
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"

Documentation (Optional)

• In case of new functionality, my PR adds documentation in the following wiki page:

(Link the GitHub wiki you added)

Code Quality

• My diff has been formatted using helix-style.xml
  (helix-style-intellij.xml if IntelliJ IDE is used)

[narendly]

Looks good! 👍

[jiajunwang]

This PR is ready to be merged.