CLOUDSTACK-10330: Add PULL_REQUEST_TEMPLATE (#2489)

This adds a standard pull request template.

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>

PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,34 @@
+## Description
+<!--- Describe your changes in detail -->
+
+<!-- For new features, provide link to FS, dev ML discussion etc. -->
+<!-- In case of bug fix, the expected and actual behaviours, steps to reproduce. -->
+
+## Types of changes
+<!--- What types of changes does your code introduce? Put an `x` in all the boxes that apply: -->
+- [ ] Breaking change (fix or feature that would cause existing functionality to change)
+- [ ] New feature (non-breaking change which adds functionality)
+- [ ] Bug fix (non-breaking change which fixes an issue)
+- [ ] Enhancement (improves an existing feature and functionality)
+- [ ] Cleanup (Code refactoring and cleanup, that may add test cases)
+
+## Screenshots (if appropriate):
+
+## How Has This Been Tested?
+
+<!-- Please describe in detail how you tested your changes. -->
+<!-- Include details of your testing environment, and the tests you ran to -->
+<!-- see how your change affects other areas of the code, etc. -->
+
+## Checklist:
+<!--- Go over all the following points, and put an `x` in all the boxes that apply. -->
+<!--- If you're unsure about any of these, don't hesitate to ask. We're here to help! -->
+- [ ] I have read the [CONTRIBUTING](https://github.com/apache/cloudstack/blob/master/CONTRIBUTING.md) document.
+- [ ] My code follows the code style of this project.
+- [ ] My change requires a change to the documentation.
+- [ ] I have updated the documentation accordingly.
+- [ ] I have added tests to cover my changes.
+- [ ] All new and existing tests passed.
+
+<!-- The following will kick a packaging job, remove if as applicable -->
+@blueorangutan package