NXP-10146: add widgetdescriptors on operation and serialize them in JSON
NXP-10146: add widget description on DocumentPageProviderOperation
NXP-10146: move Widget Descriptor transformation at contribution registration level
NXP-10146: don't hardcode operation contrib
NXP-10146: add widget description on Query operation
NXP-10146: chains don't have widgets
NXP-10146: adapt + complete tests
NXP-10146: format
NXP-10146: fix test
NXP-10146: don't serialize widgets array if empty
Revert "NXP-10146: don't serialize widgets array if empty"

This reverts commit 8675cfdac2b45362043f24d0d74fc1fa8cf93c02.