Evaluate to create native jars and plain java jar as primary deployment model

[rmannibucau]

Follow up of #834

Goal: avoid to duplicate code in all jars deployed on central

Proposal:

• keep a duckdb_jdbc with duckdb_jdbc_java + duckdb_jdbc_$native 4 libs as dependencies (pom)
• create a jar per native binary (.so/.dll) which only contain this file (and the manifest.mf)
• create a jar containing only the java code (nolib classifier today)

the integration doesn't have a fat jar anymore - but this only use case is when you create a project manually which is (almost) never today since almost all projects are maven/gradle based.