Heat source terms by domain

[rtimms]

Description

Add variables e.g. "Negative electrode Ohmic heating [W.m-3]".

Note: depending on which submodel is used, "Electrolyte current density" isn't always a concatenation, so can't be split by domain. Should be able to change this though?

Motivation

No response

Possible Implementation

No response

Additional context

No response

[rtimms]

tagging @aabills

[aabills]

The issue with electrolyte current density still stands, so I don't think we can close this.

But, it should be closed by the second part of our intended submodel refactor, which should change the electrolyte current density.