docs(): add issue template for github issues.

* Adds a issue template to the GitHub Repository.

Closes #8287

Author: devversion

CONTRIBUTING.md renamed to .github/CONTRIBUTING.md

@@ -0,0 +1,24 @@
+**Actual behavior**:
+-  What is the issue? *
+-  What is the expected behavior?
+
+**CodePen** or Steps to reproduce the issue: *
+-  CodePen Demo which shows your issue :
+-  Details:
+
+**Angular Versions**: *
+-  Angular Version:
+-  Angular Material Version:
+
+**Additional Information**:
+-  Browser Type: *
+-  Browser Version: *
+-  OS: *
+-  Stack Traces:
+
+----
+Shortcut to create a [new CodePen Demo](http://codepen.io/team/AngularMaterial/pen/bEGJdd).
+Note: `*` indicates required information. Without this information, your issue may be auto-closed.
+
+> Do not modify the titles or questions. Simply add your responses to the ends of the questions.
+  Add more lines if needed.