Check whether the mesh is periodic when non-periodic BCs are used

Discovered by @gregorgassner: We can, say, pass non-periodic `boundary_conditions` to the `SemidiscretizationHyperbolic` while the `TreeMesh` is still periodic by default. It would be nice to have some check whether that's the case and warn the user appropriately (or abort). The other way round may be even more problematic...