add Github Issue/PR templates

Summary:
This diff set up issue templates and pull request template on Hermes
GitHub repo. They should greatly help with guiding OSS users.

The structure and wording heavily borrowed from React and RN, with some
tweaks to better suit Hermes's needs.

Reviewed By: mhorowitz

Differential Revision: D22362391

fbshipit-source-id: 42baaa0283e95572a07e5a1fbbc17d7e471335aa

.github/ISSUE_TEMPLATE/01_bug_report.md

@@ -0,0 +1,46 @@
+---
+name: "🐛 Bug Report"
+about: Report a reproducible bug or regression.
+title: ''
+labels:
+- 'need triage'
+- 'bug'
+
+---
+
+## Bug Description
+
+<!--
+  Please provide a clear and concise description of what the bug is.
+
+  If it's an exception, please include the screenshots, e.g. the React Native
+  RedBox screen includes a symbolicated JavaScript stack trace with a stack trace
+  when Metro is running (it's grayscale monospaced text on black background below
+  the red background section). Please also include a few lines of the JavaScript
+  source before and after the line in which the error occurs.
+
+  If it's an abort (e.g. app crashes), please try to provide native stack trace  
+  to assist with debugging.
+-->
+
+- [ ] I have run `gradle clean` and confirmed this bug does not occur with JSC"
+
+Hermes version:
+React Native version (if any):
+Android version (if any):
+Platform (most likely one of arm64-v8a, armeabi-v7a, x86, x86_64):
+
+## Steps To Reproduce
+
+<!--
+  Your bug will get fixed much faster if we can run your code. Issues without
+  reproduction steps or a minimal, reproducible code examples may be
+  immediately closed as not actionable.
+-->
+
+1.
+2.
+
+code example:
+
+## The Expected Behavior

.github/ISSUE_TEMPLATE/02_feature_request.md

@@ -0,0 +1,29 @@
+---
+name: "🚀 Discussion & Feature Request"
+about: Discuss an idea or propose improvement.
+title: ''
+labels:
+- 'enhancement'
+
+---
+
+## Problem
+
+<!--
+  Thank you for starting a discussion about Hermes!
+  Is your discussion / feature request related to a problem?
+  Please provide a clear and concise description of what the problem is.
+-->
+
+## Solution
+
+<!--
+  Describe the solution you'd like to happen.
+  Also, describe the alternatives you've considered.
+-->
+
+## Additional Context
+
+<!--
+  Add any other context or screenshots about the discussion and feature request.
+-->

.github/ISSUE_TEMPLATE/03_website_doc.md

@@ -0,0 +1,16 @@
+---
+name: "📗 Website & Documentation Issue"
+about: Report a bug or propose an idea to the Hermes website & docs.
+title: ''
+labels: ''
+
+---
+
+## Description
+
+<!--
+  Please provide a clear and concise description of what the bug or the idea is.
+  Include screenshots if needed.
+
+  More details make issues more actionable for us and help us prioritize!
+-->

.github/ISSUE_TEMPLATE/04_thanks.md

@@ -0,0 +1,14 @@
+---
+name: ❤️ Say thank you
+about: Tell us how you use Hermes
+title: ''
+labels: ''
+
+---
+
+## ❤️ I'm using Hermes!
+
+<!--
+  If you (or your company) are using Hermes - please let us know.
+  We'd love to hear from you!
+-->

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,4 @@
+contact_links:
+  - name: ⚛️ Need Help From React Native?
+    url: https://github.com/facebook/react-native/issues
+    about: Consider file an issue in the React Native repository.

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,27 @@
+<!--
+  Thanks for submitting a pull request!
+  We appreciate you spending the time to work on these changes. Please provide enough information so that others can review your pull request. The two fields below are mandatory.
+
+  Before submitting a pull request, please make sure the following is done:
+
+  1. Fork [the repository](https://github.com/facebook/hermes) and create your branch from `master`.
+  2. If you've fixed a bug or added code that should be tested, add tests!
+  3. Ensure it builds and the test suite passes. [tips](https://github.com/facebook/hermes/blob/master/doc/BuildingAndRunning.md)
+  4. Format your code with `.../hermes/utils/format.sh`
+  5. If you haven't already, complete the CLA.
+-->
+
+## Summary
+
+<!--
+  Explain the **motivation** for making this change.
+  What existing problem does the pull request solve?
+-->
+
+## Test Plan
+
+<!--
+  Demonstrate the code is solid.
+  Example: The exact commands you ran and their output,
+  screenshots / videos if the pull request changes the user interface.
+-->

doc/BuildingAndRunning.md

@@ -67,13 +67,19 @@ The primary binary is the `hermes` tool, which will be found at `build/bin/herme
     hermes -emit-binary -out test.hbc test.js
     hermes test.hbc
 
-
 ## Running Tests
 
 To run the Hermes test suite:
 
     ninja check-hermes
 
+## Formatting Code
+
+To automatically format all your changes, you will need `clang-format`, then
+simply run:
+
+    hermes/utils/format.sh
+
 ### Other Tools
 
 In addition to `hermes`, the following tools will be built: