Remove no-longer-needed lifecycle mapping config

Thanks to an improvement in nar-maven-plugin 3.0.0, it is no longer
necessary to put this verbose configuration block into every POM that
wishes to use NAR in conjunction with Eclipse.

See: https://github.com/maven-nar/nar-maven-plugin/commit/9b3e00fd5a0924eaaa4e9edd7a5b1f2c265a57b2