Bug#900763: maven-debian-helper: Install the dependency reduced pom when the shade plugin is used

[Emmanuel Bourg]

Package: maven-debian-helper
Severity: wishlist

When the maven-shade-plugin is used, an alternate pom named
dependency-reduced-pom.xml is generated with the right dependencies for the
artifact generated. maven-debian-helper should install this pom in the binary
package instead of the original one. The package dependency resolution should
also be based on this dependency reduced pom to avoid adding dependencies
that were embedded into the jar. Ideally, the Built-Using field in
debian/control should be updated automatically in this case.

src:libpgjava is an example of package that could be simplified with this
improvement. Currently libpgjava has to mark the embedded dependencies as
'provided' to make them optional at compile time and neutral for the package
dependency resolution.