Use SystemPropertiesAnalysis to get more statically known Strings

[errt]

We have an analysis that identifies Strings set as system properties, use it for, e.g., reflection analysis.

This is WIP, as dependency handling and type changes (Set[String] instead of String) still have to be done. I won't continue on this for now.

@johannesduesing I assigned you to this, as it is part of the greater task of more proper string analysis that also includes PR #1

[johannesduesing]

/it:test

EDIT: This comment was used to test whether the changes introduced in #155 actually work as intended - which they seem to do, the job status is set to pending as expected.

[maximilianruesch]

Note: Work on the string analysis from PR #1 includes work on the system properties analysis. Thus, if #1 is merged, we can close this PR.