Push down parameters & methods

[jglick]

Looking at sources I noticed that a lot of mojo parameters and helper methods were defined in an unnecessarily high superclass (used only in a specific subclass). Trying to push down things into more appropriate places.

Also removing gratuitous getter/setter pattern in favor of simple fields (https://maven.apache.org/guides/plugin/guide-java-plugin-development.html#defining-parameters-within-a-mojo clarifies that the JavaBeans pattern is an option helpful for integrating with other code, which is not relevant in this context) and limiting Java access to private or protected as appropriate.

• review all members of AbstractJenkinsMojo
• review all members of AbstractHpiMojo
• review all members of AbstractJenkinsManifestMojo
• restore members to original sort order