Update POMs to deploy Maven artifacts to repository.apache.org and use ASF parent POM

As per Apache infra's request Maven artifacts should be deployed to repository.apache.org.
Derby is currently deploying to people.apache.org, for which Maven deployment will be disabled in Jan 2013.

Additionally, the Derby POMs should refer to the ASF top-level POM as the parent. There are several advantages to doing this, see [1] for details.

[1] http://www.apache.org/dev/publishing-maven-artifacts.html#inherit-parent