Add guidelines when opening an issue (#2123)

Based on an idea of @Yoginth.

issue_template.md

@@ -0,0 +1,16 @@
+<!--
+If you need technical help please read https://www.wappalyzer.com/docs before opening an issue.
+It also explains well how to add a new application detection.
+-->
+
+**Do you want to request a *feature*, a *new application detection* or report a *bug*?**
+
+**Is your issue about WebExtension driver (Chrome & Firefox), the website, the NPM driver or the bookmarklet ?**
+
+**What is the current behavior ?**
+
+**If the current behavior is a bug, please provide the steps to reproduce and if possible a demo of the problem.**
+
+**What is the expected behavior ?**
+
+**Which versions of Wappalyzer, and which browser / OS are affected by this issue ? Did this work in previous versions ?**