Improve error messages for semantic errors

[maxhoerstr]

Currently not all semantic error messages are printed correctly or at all. Due to the fact that the semantic check is executed after the parsing, a way of saving the context infos had to be implemented. Currently, not all informations about the specific parts of the program are saved. Find a way to preserve the context information for every bit of PFDL code in the SemanticErrorChecker to provide proper error messages.

An example for this issue is shown below:

The attribute not an attribute is not defined in the Struct Color. The error highlight should appear in the same row as the attribute and not at the Struct name. Currently, the SemanticErrorChecker do not have enough information to display it at the correct position.