Units VA/MVA do not match newest units in MSL

[maltelenz]

In the Modelica Standard Library, it was chosen to use V.A as a unit, as opposed to VA, see https://github.com/modelica/ModelicaStandardLibrary/issues/2076

PowerSystems uses VA, as well as the displayUnit MVA. Should it switch to use V.A and MV.A to match the standard library?

[rfranke]

Thank you for this hint.