Add templates for issues and pull requests

GitHub recently introduced templates for issues and PRs.
These will hopefully improve both.

//FREEBIE

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,36 @@
+<!--
+Please note that this is an issue tracker
+
+For support go to the Support Center:
+http://support.whispersystems.org/
+or email support@whispersystems.org
+
+For discussion go to the community forum:
+https://whispersystems.discoursehosting.net
+
+Delete any sections that aren't relevant.
+-->
+
+<!-- mark with x between the [ ] -->
+- [ ] I have searched open and closed issues for duplicates
+
+
+### Bug description
+
+
+### Steps to reproduce
+- add your steps here
+- as a list
+- using hyphens
+
+### Screenshots
+<!-- you can drag and drop images here -->
+
+
+### Platform info
+<!-- replace examples with your info -->
+**Operating System**: My Operating System A
+**Browser**: My Browser X.Y.Z
+**Signal version:** Z.Y.Y
+
+### Link to debug log