[PDI-9309]: Fixed build, package, source, and i18n issues

Fixes:

- The Vertica Bulk Loader is a PDI step plugin, which should be packaged according to targets defined in subfloor-pkg.xml.  This project did not include that file and instead had an approach that created a published artifact that differed from the artifact collected by the CI job.

- The step dialog would not show up because without overriding a particular method, PDI will expect the dialog class to have a "ui" in the package name before the name of the step package. I moved the dialog class to the expected package

- Moving the dialog class out of its original package caused me to have to change the PKG class to the meta class (rather than itself) so the localization/internationalization stuff would still work.

- Using the standard subfloor-pkg targets caused the need for some refactoring commensurate with most PDI step plugins, such as moving the plugin JAR to the root of the ZIP, including a "provided" Ivy configuration for PDI-provided JARs, adding a package-res folder containing only a .gitignore file (to force its inclusion in Git), etc.

- I wasn't sure about the versions of the flexjson and json dependencies for this plugin, so I left them as default dependencies instead of having them be provided by PDI, to avoid any potential version conflicts.