Add some basic project stuff

Motivation

The project was missing some basic information and configuration until now. This includes a license as well as some templates for issues and merge requests.

Modifications

• add the following files
  • AGPL license
  • template for merge requests
  • template for bug reports
• extend README.md

Result

• The license is visible in the project information
• Merge requests are created with our standard template
• Bug reports are in a standard format
• README.md contains basic information about the project