Add issue templates

.gitlab/issue_templates/Bug.md

@@ -0,0 +1,22 @@
+**Please first check if another issue has been opened for your problem**
+
+## Versions
+
+  - OS: 
+  - Gajim version: 
+  - Plugin version: 
+  - GTK version: 
+  - Python-nbxmpp version: 
+
+## Steps to reproduce the problem
+
+  1.
+  1.
+  1.
+
+## Expected behavior
+
+
+## Actual behavior
+
+