Apply official jOOQ gradle plugin when adding the jOOQ feature. [skip ci]

[wetted]

closes #2228

[wetted]

This still needs work. The jooq gradle plugin fails if the buiild doesn't define jooq { configuration { database {} } }.

[wetted]

This PR needs two things:

• apply the jooq gradle plugin iff both the jooq feature and a configurable database feature are selected
• create a rocker template to contribute the jooq {} configuration to the build (otherwise the build fails)

[wetted]

I haven't yet figured out how to do the Flyway generation from the joog-gradle-plugin.

I have a personal playground project for this at: https://github.com/wetted/jooq-gradle.git