Adds issue template, minimalistic, open for discussion. Refs #1847

Author: JJ

.github/issue_template.md

@@ -0,0 +1,15 @@
+<!-- Thanks a lot for your contribution. If applicable, please try to follow this template to report an issue -->
+
+I'm reporting
+
+- [ ] A problem with the site (something does not show up in the search drop-down menu or a page is missing, for instance)
+- [ ] Documentation text or examples that are missing or should be improved
+- [ ] Something else
+
+## Bug report
+
+<!-- describe the problem, the page where you have found it -->
+
+## Suggestions
+
+<!-- If applicable, state what could be done to solve the problem, such as "Rephrase the description" or "Use an example program that actually runs" -- >