code: public static String resolvePath(final OperationContext context, final String relativeToPath, final String path) {
          return INSTANCE.resolve(context, relativeToPath, path);
      }
docs: Resolves the path based on the relative to and the path. May return {@code null} if the service is not up.
  
  @param context        the operation context.
  @param relativeToPath the relative to path, may be {@code null}.
  @param path           the path to append to the relative to path or the absolute path if the relative to path is
  {@code null}.
  
  @return the full path or {@code null} if the services were not started.