Implement dynamic viscosity models:
- PhQ::DynamicViscosityModel
- PhQ::DynamicViscosityModel::Constant
- PhQ::DynamicViscosityModel::TemperatureTable
- PhQ::DynamicViscosityModel::Sutherland
See https://en.wikipedia.org/wiki/Temperature_dependence_of_viscosity
Requires #205