Improve exception safety with smart pointers

[elfring]

Would you like to wrap any pointers with the class template “std::unique_ptr”?

[sjunges]

Not any, but we do of course welcome increased memory safety.

[elfring]

:thought_balloon: Would you become interested to use a development tool like “clang-tidy” for corresponding source code adjustments?

[sjunges]

We welcome pull requests that improve the code quality. Integrating CI based on clang-tidy is not a priority right now.

[elfring]

:crystal_ball: Will a special data representation trigger another bit of collateral evolution? https://github.com/moves-rwth/storm/blob/66981bb05f2a5ff67ea89ac6709d3aab581c9a16/src/storm-gspn/parser/GspnParser.cpp#L15-L74