The 'name' in process construction is also used after
the process construction and so it can not be moved
anyway. Taking it by const-ref avoids an extra copy
here (and silences a cppcheck warning).

This unifies the doxygen headers. If the (doxygen) header is not
starting with \file, the following documentation is attributed to a
different entity resulting is multiple copyright blocks and the like in
the doxygen's html files.

Make the linearity property of LiquidFlow proces configurable

Output of surface flux uses the standard mesh
output. Therefore it isn't necessary anymore to
pass the output_directory.

Mv porosity/storage from solid to medium properties.

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

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%'

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.

This versions check if the PropertyVector is
assigned to the requested mesh item type and has
the required number of components.