Link delete-project plugin

The pull-replication plugin depends on the code from the delete-project
plugin and requires it to be deployed to the Gerrit's `lib/` directory.
Which is making the pull-replication plugin deployment more complex.

By linking with delete-project plugin directly, we indluce its classes
into our JAR file simplifying the deployment process.

Change-Id: I580a8a44d7a722a91442a1b8f6f3f653e8f40b46