Adding issue template (#403)

ISSUE_TEMPLATE.md

+# Prerequisites
+
+Your issue may already be reported!
+Please search on the [issue track](https://github.com/threat9/routersploit/labels/bug) before creating one.
+
+! INCOMPLETE REPORTS WILL BE CLOSED. PLEASE REMOVE THIS PART AND LEAVE ONLY THE FOLLOWING SECTIONS IN YOUR REPORT. !
+---
+
+## Your Environment
+<!--- Include as many relevant details about the environment you experienced the bug in -->
+* RouterSploit Version used:
+* Operating System and version:
+* Python Version: ( `python3 --version` )
+* Python Environment: ( `python3 -m pip freeze` )
+
+## Steps to Reproduce (for bugs)
+<!--- Provide a link to a live example, or an unambiguous set of steps to -->
+<!--- reproduce this bug. Include code to reproduce, if relevant -->
+1.
+2.
+3.
+4.
+
+## Expected Behavior
+<!--- If you're describing a bug, tell us what should happen -->
+<!--- If you're suggesting a change/improvement, tell us how it should work -->
+
+## Current Behavior
+<!--- If describing a bug, tell us what happens instead of the expected behavior -->
+<!--- If suggesting a change/improvement, explain the difference from current behavior -->