Support OSGi 7

The Maven Bundle Plugin generates this Beans-Manifest:

    beans="a.Controller"

But this is Expected in OSGi 7:

    beans:List<String>="a.Controller"

As you see here the Maven Bundle Plugin can not generate OSGi 7 capable libraries.

The cause of the problem is that beans in the Manifest.MF should be declared as a List of String, instead of a String.
Official documentation:

https://docs.osgi.org/specification/osgi.enterprise/7.0.0/service.cdi.html#org.osgi.service.cdi.CDIConstants.REQUIREMENT_BEANS_ATTRIBUTE