This commit extends class WellStateFullyImplictBlackoil to report
segment-related quantities as Opm::data::Segment objects (included
in Opm::data::WellRates objects). All wells have at least a top
segment in the context of WellState FIBO, so there is a meaningful
value to report for each well.
We put the extraction of segment-related quantities into a new
helper function
WellStateFullyImplicitBlackoil::reportSegmentResults()
to avoid cluttering up the body of report() more than absolutely
needed.
The primary use-case for this is assigning appropriate values to
items 8 through 11 of restart vector RSEG. In turn, this will
enable restoring these quantities from a restart file.