Delete old issue template

.github/issue_template.md

-**Bug Report** or **Feature Request**
-
-For general questions please use [PX4 Discuss](http://discuss.px4.io/) or [Slack](slack.px4.io). Issue reports need to contain the items below:
-
- - Download the flight log file from the vehicle ([tutorial](https://docs.px4.io/en/flight-reporting.html))
- - Share the link to a log showing the problem on [PX4 Flight Review](http://logs.px4.io/)
- - Expected behavior and actual behavior.
- - Steps to reproduce the problem.
- - Specifications like the version of the project, operating system, or hardware.