Move boltzmann to cell spaces

[quaquel]

With cell spaces now stable, we need to update the basic examples. This PR does so for the boltzmann model.

[github-actions]

Performance benchmarks:

Model	Size	Init time [95% CI]	Run time [95% CI]
BoltzmannWealth	small	🔴 +92.3% [+90.3%, +94.2%]	🟢 -17.6% [-17.8%, -17.4%]
BoltzmannWealth	large	🔴 +139.7% [+103.1%, +216.2%]	🔵 -1.4% [-3.0%, +0.4%]
Schelling	small	🔵 +0.2% [-0.1%, +0.5%]	🔵 -0.2% [-0.4%, +0.0%]
Schelling	large	🔵 -0.2% [-0.6%, +0.1%]	🔵 -0.5% [-1.1%, +0.4%]
WolfSheep	small	🔵 -2.2% [-2.7%, -1.7%]	🔵 +0.8% [+0.6%, +1.0%]
WolfSheep	large	🟢 -4.4% [-5.5%, -3.2%]	🔵 -4.7% [-7.4%, -1.3%]
BoidFlockers	small	🔵 -1.2% [-2.0%, -0.4%]	🔵 +0.0% [-0.2%, +0.3%]
BoidFlockers	large	🔵 +0.1% [-0.7%, +1.3%]	🔵 -0.1% [-0.6%, +0.4%]