Remove frictional wall heating from incompressible wall function model

[bigfooted]

Proposed Changes

The wall function model of Nichols and Nelson was basically implemented in the same way for the compressible and the incompressible solver. But for the incompressible solver, the frictional heating part does not make sense, so it is removed. In the compressible part, some lines have been moved to make comparison between the comp/incomp model easier.

Related Work

PR Checklist

Put an X by all that apply. You can fill this out after submitting the PR. If you have any questions, don't hesitate to ask! We want to help. These are a guide for you to know what the reviewers will be looking for in your contribution.

• I am submitting my contribution to the develop branch.
• My contribution generates no new compiler warnings (try with --warnlevel=3 when using meson).
• My contribution is commented and consistent with SU2 style (https://su2code.github.io/docs_v7/Style-Guide/).
• I have added a test case that demonstrates my contribution, if necessary.
• I have updated appropriate documentation (Tutorials, Docs Page, config_template.cpp), if necessary.

[pcarruscag]

LGTM