StreamingStatisticsMapFromLabelImageFilter no data support

Summary

• add a progress reporter
• reduce copying and lookups in otb::StreamingStatisticsMapFromLabelImageFilter
• add support for ignoring pixels containing a certain value ("no data")

Rationale

When processing time series, it often happens that some values are missing. These changes make it possible to compute the various statistics while ignoring these no data values.

The statistics are still computed independently for each band, so a no data value in one of the bands does not exclude the pixel from the computation of the statistics for the bands.

Implementation Details

The three changes are separate commits to make reviewing easier.

Additional notes

I'm not sure if adding the itk::ProgressReporter is enough, no progress seemed to be displayed in my quick test.

Copyright

The copyright owner is CS ROMANIA / Laurențiu Nicola and has signed the ORFEO ToolBox Contributor License Agreement.

---

***Check before merging:*** - All discussions are resolved - At least 2 votes from core developers, no vote. - The feature branch is (reasonably) up-to-date with the base branch - Dashboard is green - Copyright owner has signed the ORFEO ToolBox Contributor License Agreement