Use io.spring.maven.antora

[rwinch]

This switches to using io.spring.maven.antora plugins which does two things:

• corrects the Antora build by using antora-component-version-maven-plugin to generate the version and prerelease attributes
• Simplifies the Antora build configuration
• Adds a new lifecycle method. Now building Antora is just mvn antora This means that it should not need to be behind a profile since it is not longer invoked with the compile phase.