* Declare CHECKSTYLE_VERSION class member constant in the CheckstylePlugin.
* Remove the PlublishLocalPlugin.
* Replace use of the deprecated JavaPluginConvention with JavaPluginExtension in the JavadocApiPlugin.
* Replace the EclipseWtpPlugin with the EclipsePlugin applied in the AbstractSpringJavaPlugin class.
* Review and fix spelling error in CopyPropertiesPlugin Javadoc.
* Review, refactor and polish the Spring Gradle PropDepsPlugins including PropDepsPlugins for IntelliJ IDEA and Eclipse.