General Improvements and Bug Fixes for OWASP-Nettacker

OWASP Nettacker is a project that automatically gathers information, scans network for vulnerabilities and eventually generates a report for networks, including services, bugs, vulnerabilities, misconfigurations, and other information. A lot of small improvements can be done to Nettacker. A lot of features have been mentioned in the issue tracker but have remained stagnant since then. I plan to add most of these features (tagged as both enhancement and help wanted) by the end of GSoC period and keep fixing bugs reported during the GSoC period.