code: @Nonnull
    public final JettyStarter setResourceBase (@Nonnull final Resource aResourceBase)
    {
      ValueEnforcer.notNull (aResourceBase, "ResourceBase");
      m_aResourceBase = aResourceBase;
      return this;
    }
docs: Set the common resource base (directory) from which all web application
  resources will be loaded (servlet context root).
  
  @param aResourceBase
  The resource. May neither be <code>null</code> nor empty.
  @return this for chaining