Upgrade nebula Nattable from 1.5.0 to 1.6.0

• Mirror nattable release 1.6.0 to https://www.simantics.org/update/nebula/nattable/releases/1.6.0/
• Update org.simantics.sdk.build.targetdefinition.tpd to use the 1.6.0 repository and upgrade all platform .tpd/.target files
• Rebuild simantics.tpd target
• Rebuild simupedia targets