corrected explicit energy solve forced to remain forward euler.

[colemanjs]

This PR have several changes focused on improving AdditiveFOAM for the JOSS review.

1. The logic of the adaptive integration of the energy equation was updated to force the explicit solve using forward euler.
2. ExaCA support was added for all heat transfer tutorials based on JOSS review comments.
3. The foamToExaCA code was made into a FunctionObject to improve its IO handling.
4. A new Allwmake script was added to the solver to collectively build the ExaCA FunctionObject, heatSourceModel library, and additivefoam solver.

Upon approval, the documentation needs to be updated at (https://ornl.github.io/AdditiveFOAM)

[kincaidkc]

Do we want to include the foamToExaCADict for the tutorials but set execute to off by default?

[colemanjs]

Do we want to include the foamToExaCADict for the tutorials but set execute to off by default?

I think that OpenFOAM generally will enable execution if the configuration file and all arguments are provided in a case directory. Maybe we should just make foamToExaCADict a fuctionObject so that it inherits the expected OpenFOAM IO handling? Thoughts?

[kincaidkc]

Looks good, glad we moved foamToExaCA to a function object and corrected the boundary condition naming convention.