Add bug template

.gitlab/issue_templates/bug.md

+---
+**NOTE**
+
+Issues for **core apps** can be filed in their respective existing repositories:
+* [Libhandy](https://source.puri.sm/Librem5/libhandy/issues) - GTK+ library for developing UIs for applications
+* [Calls](https://source.puri.sm/Librem5/calls/issues) - phone calling application
+* [Chatty](https://source.puri.sm/Librem5/purism-chatty/issues) - messaging application
+* [Phosh](https://source.puri.sm/Librem5/phosh/issues) - shell
+* [Virtboard](https://source.puri.sm/Librem5/virtboard/issues) - onscreen keyboard
+
+Issues relating to **non-core apps** can be filed under:
+* [Apps issues](https://source.puri.sm/Librem5/Apps_Issues/issues)
+
+File an issue in this repo for issues pertaining to the general operating system of the Librem 5
+
+---
+
+# What problem did you encounter
+
+## What is the actual behaviour?
+
+## What is the expected behaviour?
+
+## How to reproduce
+
+  Please provide steps to reproduce the issue. If it's a graphical issue please
+  attach screenshots.
+
+# What hardware are you running on?
+
+ - [ ] amd64 qemu image
+ - [ ] Librem5 devkit
+ - [ ] other (please elaborate)
+
+# Relevant OS information
+
+## Which kernel are you using?
+
+  Please paste the output of ``uname -a`` below.
+
+## Which OS are you using?
+
+  Please paste the output of ``cat /etc/os-release`` below.
+
+## Any other information that may be helpful?
+
+  Depending on the nature of the issue, you may consider adding the output of:
+  * lsblk (for mounting issues)
+  * lsusb (for usb attachment issues)
+  * any journalctl logs that look suspicious
+  * etc.