Add GitHub PR and Issue templates

Add the GitHub PR and Issue templates used by the KubeVirt org.

Signed-off-by: Felix Matouschek <fmatouschek@redhat.com>

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,31 @@
+<!-- This form is for bug reports and feature requests ONLY!
+Also make sure that you visit our User Guide at https://kubevirt.io/user-guide/
+-->
+
+**Is this a BUG REPORT or FEATURE REQUEST?**:
+
+> Uncomment only one, leave it on its own line:
+>
+> /kind bug
+> /kind enhancement
+
+
+**What happened**:
+
+**What you expected to happen**:
+
+**How to reproduce it (as minimally and precisely as possible)**:
+
+
+**Anything else we need to know?**:
+
+**Environment**:
+- KubeVirt version (use `virtctl version`):
+- Kubernetes version (use `kubectl version`):
+- common-templates version:
+- VM or VMI specifications:
+- Cloud provider or hardware configuration:
+- OS (e.g. from /etc/os-release):
+- Kernel (e.g. `uname -a`):
+- Install tools:
+- Others:

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,19 @@
+<!--  Thanks for sending a pull request!  Here are some tips for you:
+1. Follow the instructions for writing a release note from k8s: https://git.k8s.io/community/contributors/guide/release-notes.md
+-->
+
+**What this PR does / why we need it**:
+
+**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
+Fixes #
+
+**Special notes for your reviewer**:
+
+**Release note**:
+<!--  Write your release note:
+1. Enter your extended release note in the below block. If the PR requires additional action from users switching to the new release, include the string "action required".
+2. If no release note is required, just write "NONE".
+-->
+```release-note
+
+```