Handle icon property from OperationAction in the compatibility layer

[AxelRICHARD]

• I have checked that this feature has not yet been suggested by someone else.

Expected behavior

Unlike many others concept in the odesign, OperationAction handles custom icon through the icon property instead of the iconPath property.
ToolImageProvider only handles iconPath property for now.
An improvement could be to also handle icon property in ToolImageProvider.

[sbegaudeau]

Closing this since it has been merged

[sbegaudeau]

Reopening this issue since the commit has not been merged, it only exists on the fork here :)