The cache significantly increases compile time

[Sbozzolo]

From CliMA/ClimaCore.jl#1467

Tuples of Fields affect compilation time and are a major cause of latency.

In ClimaAtmos, the cache is a massive tuple. A native restructuring of the cache from a tuple to a struct shows 60% latency reduction to get the integrator for a moist case without radiation. The latency is further reduced for more complex cases.

[simonbyrne]

See #2217