PVD support was implemented already.

Adding a single space in incorrectly broken lines.

Fixes clang-tidy warning bugprone-use-after-move.

Use const references where necessary.

Especially useful when all nonlinear iterations should
be output. See <output_iteration_results> tag.

Makes hdf5 and libxml2 dependencies optional.

Apply 17 suggestion(s) to 6 file(s)

contains fix: iteration output was overwritten at each timestep because name
did not include timestep or time.
implementation note: Replaced time by iteration because of missing functionality
in BaseLib::constructFormattedFileName to handle iterations

- rename to makeoutput

The previous implementation would miss a fixed output time
if the time step was repeated.

Since for one process output on multiple
(sub)domains / meshes can be required it is
necessary to manage multiple pvd files. All pvd
files for all processes are stored in a multimap.
The findPVDFile method is extended to find the
correct pvd file for the corresponding domain and
process.

For processes containing multiple subprocesses
(staggered scheme and component transport) it
isn't allowed to contain the process id in the
output prefix template.