Align readout values

[planetchili]

Auto-migrated from intel-sandbox/applications.graphics.presentmonservice/issues/292

^{Original creation by planetchili on 2023-07-07 02:11:18+00:00}

allowing free sizing of readout text means that right left justification strategy w/ max container width no longer works well
devolved behavior to fixed margin after label, so values no longer align
need to decide how to address this issue. might involve adding new capabilities to the layout/style engine.
suggestion by Rado: instead of separating label and value, justify towards a centerline and align there
value on left might make this viable, with fixed value/unit width and remaining size allocated to label
one issue here is how to show the units: see ocat screenshot