code: protected Path createPluginsRoot() {
          String pluginsDir = System.getProperty("pf4j.pluginsDir");
          if (pluginsDir == null) {
              if (isDevelopment()) {
                  pluginsDir = "../plugins";
              } else {
                  pluginsDir = "plugins";
              }
          }
  
          return Paths.get(pluginsDir);
      }
docs: Add the possibility to override the plugins root.
  If a {@code pf4j.pluginsDir} system property is defined than this method returns that root.
  If {@link #getRuntimeMode()} returns {@link RuntimeMode#DEVELOPMENT} than {@code ../plugins}
  is returned else this method returns {@code plugins}.
  
  @return the plugins root