Add bug report issue template (#880)

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,30 @@
+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: T-Defect
+assignees: ''
+
+---
+
+<!--
+Before creating an issue, please consider whether the issue belongs here or in another app repository.
+If you discovered the bug in a Matrix client, please first raise a corresponding issue in that repository and link to that issue here.
+-->
+
+## Problem
+<!-- A short description of the problem -->
+
+## Steps to reproduce
+<!--
+Any of the following would help us greatly:
+- A failing test demonstrating the issue.
+- Steps to manually reproduce the issue in one of the example projects.
+- A screen recording of you manually reproducing the issue in one of the example projects.
+-->
+
+## Related issues
+<!-- If applicable -->
+
+## Proposed solution
+<!-- If applicable -->