gitlab: Add some simply issue templates

.gitlab/issue_templates/bug.md

+# Summary
+
+Write a brief description of the issue.
+
+# Steps to reproduce
+
+Please provide a set of concrete steps to reproduce the issue.
+
+# Expected behavior
+
+What do you expect the reproducer described above to do?
+
+# Environment
+
+* GHC version used: 
+
+Optional:
+
+* Operating System: 
+* System Architecture: 
+
+
+/label %bug
+/label %"needs triage"