Flatten the cookbook project

The bij dependency split to a separate repository:
    https://github.com/fiji/cookbook

So now the cookbook_ code is at the root as a single-module project,
in line with all the other Fiji projects.

The project also now extends the latest pom-fiji,
to inherit all the organizational metadata.
POM: tidy up order of configuration blocks

Accomplished using:

    mvn tidy:pom