* Move some github helper files to own folder
The COPYING and CODE_OF_CONDUCT files stay in the root directory since they should be immediately accessable. The others are used automatically and linked from the pages where they are needed.
* Create ISSUE_TEMPLATE.md
* Create PULL_REQUEST_TEMPLATE.md
* Move the Code of Conduct as well
The Code of Conduct is also linked from the Issues and PR pages and can be moved