This enables outputting a formatted record of the limiting MB and
CNV quantities as time and non-linear iterations progress. This, in
turn, is intended for diagnostic and analysis purposes and will not
be output unless specifically requested.
In particular, add a new type,
ConvergenceReport::ReservoirConvergenceMetric
which captures the convergence metric type (MB or CNV) along with
the associate phase and numerical value of the convergence metric.
We add a vector of these convergence metric objects as a new data
member of the ConvergenceReport.
Finally, foreshadowing the intended use case, also store the report
time in the ConvergenceReport object.
No templates involved, no reason to keep it in header. This also makes
building more robust by only invoking HAVE_MPI in the cpp file, after
including config.h.
