HSE Cluster with Cooling

Add initial conditions for a cluster in hydrostatic equilibrium and a subcycling tabular cooling.

Adds a galaxy cluster problem generator that includes an initial cluster in hydrostatic equilibrium with an ACCEPT like entropy profile and a gravitational profile with contributions from an NFW dark matter halo, Hernquist BCG, and SMBH.

Adds a regression test of the hydrostatic equilibrium setup that initializes a spherically symmetric galaxy cluster in hydrostatic equilibrium and runs it for a short amount of time. The simulation should remain static throughout the evolution, although some drift occurs due to the finite grid. The regression test tests that the initial conditions match an equivalent model in python and that differences between the initial and final state are sufficiently small.

Adds a tabular cooling source term that subcycles cooling using a cooling rate interpolated from interpolates logarithmically spaced in T table of \log \Lambda ( \log T ). Implements adaptive RK12 and RK45 solvers for the subcycling.

Adds a cooling timestep limit based on the tabular cooling.

Adds a regression test of the tabular cooling using an exponential cooling function.