Use string analysis results for `Class.forName` reflective calls

[maximilianruesch]

Uses the results generated in #1 by:

• Integrating them into the ClassForName reflective call analysis
• Adding a string analysis demo along with a demo package showcasing the ability of the now integrated analysis to resolve calls across the Apache Xerces Framework

This PR contains some compromises and bugfixes that still need to be ironed out.