Previously for Measurement fields with .QCI or .CAUSE suffix we had only
the .sum value and no per-QCI nor per-CAUSE values. In other words
support for QCI and CAUSE was stub. In this patch we add support for
QCI: every field X.QCI is now automatically expanded into X[256] array
and X.sum . For convenience we also provide X.<qci> aliases that alias
X[qci]. For example field DRB.IPVolDl.9 aliases 9'th element of
DRB.IPVolDl array.

We will need QCI support for E-UTRAN IP Throughput KPI which is required
to provide resulting values for every QCI individually.

CAUSE support remains stub for now.