Update issue templates

Author: Vladimir Kotal

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,26 @@
+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+**Describe the bug**
+A clear and concise description of what the bug is. Make sure you have done a search of the existing issues to prevent creating duplicates.
+
+If you provide the exact version of OpenGrok, JDK used, OS(and its version) used and Tomcat(or your webapp server) used it can help figuring out an environment issue.
+For performance problem OS and JDK tunables might be needed. For SCM problems also version of SCM is helpfull (e.g. some mercurial versions have issues, some not).
+
+**To Reproduce**
+Steps to reproduce the behavior:
+
+**Expected behavior**
+A clear and concise description of what you expected to happen.
+
+**Screenshots**
+If applicable, add screenshots to help explain your problem.
+
+**Additional context**
+Add any other context about the problem here.