- Forward the output folder and mesh vector from ProjectData to CreateLiquidFlow.
- Create an optional SurfaceFluxData object.

Passing a vector of solutions now.

If only file name is specified it causes a warning
about the name not to be specific enough if there is
another file with the same name, e.g.:

the name `IdealGasLaw.h' supplied as the second argument
in the \file statement matches the following input
files: ogs/MaterialLib/Fluid/Density/IdealGasLaw.h
ogs/MaterialLib/MPL/Properties/IdealGasLaw.h
Please use a more specific name by including a (larger)
part of the path!

From now on only \file w/o a name or a full path will
be allowed.

find -type f | xargs sed -i 's%\(\\file\).*%\1%'

std::vector<std::size_t> _ids_of_active_elements.

The main change was in the creation of liquid flow process;
the succeeding changes are just adoptation to a pointer,
instead of a reference with boolean.

for flexibility in coupling.

 VectorMatrixAssemble::assembleWithJacobian

Clang format run on near-the-header lines.

Happy New Year

 from the two classes of coupled term.

[Coupling] Changed the members of the coupled term,

 which only contains the solutions of the coupled equations.

pointer to StaggeredCouplingTerm

 coupled processes.

minor changes according to Dima's comments.