Improve readme and dev workflow

[Xpirix]

Fix for #35

• Remove unused old configuration files (docs folder, backup scripts...) @timlinux , please let me know if any of the removed files (bbe1845) are still important.
• Add COPYING file (GPLv3 as mentioned in the README)
• Enhance the README and CONTRIBUTING inspired by https://github.com/kartoza/InfrastructureMapper and https://github.com/qgis/QGIS-Website
• Animated GIF of the project
• Kartoza and other contributors' credits
• Adding fixtures for quick development setup for new contributors

A live preview is available at https://github.com/Xpirix/QGIS-Changelog-Website/tree/improve_readme_and_dev_workflow

[timlinux]

Fantastic @Xpirix just the license badge is broken.

[Xpirix]

Thanks for the review @timlinux . It has been fixed now.