Remove even more solve! allocations

[1-Bart-1]

• remove calculate_results allocations
• remove other allocations
• add benchmark test

[1-Bart-1]

Closes with #126

[ufechner7]

Well, the pull requests reduces the allocations from 920 to 82, but not all allocations are removed.

[1-Bart-1]

That is good enough for now. We can add a new issue when we feel like we need to reduce more allocations ;)

[ufechner7]

Merged.