Remove the need for reinit!

[LenkaNovak]

Reinit! reinitializes the initial conditions of the state vector, as well as the integrator object. This is not ideal as it can lead to circular dependencies. The best solution is to call the initial conditions of all models separately, before initialization of any of the models' integrators. With the current ClimaAtmos interface, this is not possible.

This is a medium priority task, potentially requiring substantial interface changes / modularization, so this will be addressed after the mid-October milestone.

Necessary changes

• split up initialization of the state from the initialization of the integrator, in a way that the coupler can call these in two separate calls.
• Ensure the same is done for Land (and the other models).

Preferable changes

• modularize the Atmos driver as a whole

[LenkaNovak]

Just tagging #133 which highlights the need to take another look at reinit! in our time stepping.

[LenkaNovak]

address in #187