migrate to grade-upload and refactor glues

[fabiosimeoni]

the dsl initially implemented in grade-glue is now generalised and extracted into standalone client API for java clients, grade-upload. We need now to further refactor to use it.

also, the current distribution of tests across source files hides the overall integration picture. Id' like to move all tests to Glues, as per the original design, and maintain separate fils for source-specific post-processing steps invoked directly from the tests in Glues. These files can go in an aux package.

finally, the use of constants and utils can be more systematic and symmetric across sources. I'm including that too in the refactoring.

[eblondel]

It sounds good, i like the idea to have all grab and push methods in a single Glues but indeed keeping all post-processing methods clustered by source/theme, as we have now.

[fabiosimeoni]

pushed it, please check it out. any question is welcome here. will close when you give the thumbs up.

[eblondel]

I've investigated how to add a loadFeatures from local GML file in Commons. At now, reading GML requires to have access to the featureType. Considering the need to have atomic grab / push methods, and possible to face ows server unavailability, we should have the capacity to read local GML files vs. the GeoAPI, to reuse for post-processing and pushing. At now it's not possible with Geotk, but they reported they are working on a GMLFeatureStore that would be make this possible.