maintenance and stability release

We welcome new GSoC students (Sarthak Khattar and Shubham Pandey) in the Organization!

Main updates:

• new release of the official GUI IntelOwl-Ng
• added Malpedia analyzer

Then a lot of maintenance and overall project stability issues solved:

• removed eventlet broken dependency
• bumped new versions of a lot of dependencies
• Improved "Installation" and "Contribute" documentation
• added new badges to the README
• added --django-server option to speed up development
• analyzed files are now correctly deleted with the periodic cronjob
• other little refactors and fixes