Adding initial issue template copied from OSRF RCLCPP template (#253)

Author: Carl Delsey

.github/ISSUE_TEMPLATE.md

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+<!--
+For general questions, please ask on ROS answers: https://answers.ros.org, make sure to include at least the `ros2` tag and the rosdistro version you are running, e.g. `ardent`.
+For general design discussions, please post on discourse: https://discourse.ros.org/c/ng-ros
+Not sure if this is the right repository? Open an issue on https://github.com/ros-planning/navigation2
+For Bug report or feature requests, please fill out the relevant category below
+-->
+
+## Bug report
+
+**Required Info:**
+
+- Operating System:
+  - <!-- OS and version (e.g. Windows 10, Ubuntu 16.04...) -->
+- Installation type:
+  - <!-- binaries or from source  -->
+- Version or commit hash:
+  - <!-- Output of git rev-parse HEAD, release version, or repos file  -->
+- DDS implementation:
+  - <!-- rmw_implementation used (e.g. Fast-RTPS, RTI Connext, etc -->
+- Client library (if applicable):
+  - <!-- e.g. rclcpp, rclpy, or N/A -->
+
+#### Steps to reproduce issue
+<!-- Detailed instructions on how to reliably reproduce this issue http://sscce.org/
+``` code that can be copy-pasted is preferred ``` -->
+```
+
+```
+
+#### Expected behavior
+
+#### Actual behavior
+
+#### Additional information
+
+<!-- If you are reporting a bug delete everything below
+     If you are requesting a feature deleted everything above this line -->
+----
+## Feature request
+
+#### Feature description
+<!-- Description in a few sentences what the feature consists of and what problem it will solve -->
+
+#### Implementation considerations
+<!-- Relevant information on how the feature could be implemented and pros and cons of the different solutions -->