mosaic #290474 user, frame, display data from multiple sources [in-progress]

prioritynormal
typeenhancement
done in0.2.0
load0.500
load left0.500
closed by<not specified>
patchxmosaicsource: move sources management from xmosaicframe to xmosaicsource [applied]xmosaicsource: add fetch capability (related to #290474) [applied]components: add a new xmosaicsource component (related to #290474) [applied]