Move ncc part of equilibrium solution

[ettieunwin]

Waiting until get example from Hannah.

Remove lines 286 to 303 and put in an extra function in the user written run script. Write a vignette explaining how to do this.

[jhellewell14]

Is this fixed / still relevant?

[OJWatson]

relates to this that was in place for hannah's ivm model: https://github.com/mrc-ide/deterministic-malaria-model/blob/master/R/equilibrium-init-create.R#L285.

I think given not being released with joe's initial release this can be closed and let's just leave the ncc in there for the time being