Altair spaces

[quaquel]

This adds altair support for new-style grids (moore, von neumann and hex), as well as old-style continuous spaces

[github-actions]

Performance benchmarks:

Model	Size	Init time [95% CI]	Run time [95% CI]
BoltzmannWealth	small	🔵 +2.3% [+0.6%, +4.0%]	🔵 -0.0% [-0.3%, +0.3%]
BoltzmannWealth	large	🔵 +1.0% [+0.3%, +1.8%]	🔵 +1.4% [+0.2%, +2.8%]
Schelling	small	🔵 +0.1% [-0.2%, +0.4%]	🔵 -0.1% [-0.4%, +0.2%]
Schelling	large	🔵 -0.3% [-1.2%, +0.7%]	🔵 -0.5% [-2.4%, +1.2%]
WolfSheep	small	🔵 -0.6% [-1.1%, -0.1%]	🔵 -0.4% [-1.4%, +0.6%]
WolfSheep	large	🔵 +1.6% [-0.4%, +4.5%]	🔵 -0.6% [-3.5%, +2.1%]
BoidFlockers	small	🔵 -0.9% [-1.4%, -0.5%]	🔵 -1.2% [-1.8%, -0.6%]
BoidFlockers	large	🔵 -1.9% [-2.6%, -1.1%]	🔵 -1.9% [-2.4%, -1.5%]

[EwoutH]

Looks more robust than we currently do it, and no user API breaking changes