D23103: Add decibel power units (dBW and multiples)

[Kai Uwe Broulik]

broulik accepted this revision.

REPOSITORY
  R292 KUnitConversion

BRANCH
  log_power_units

REVISION DETAIL
  https://phabricator.kde.org/D23103

To: iasensio, broulik, ngraham
Cc: ngraham, kde-frameworks-devel, LeGast00n, GB_2, michaelh, bruns