private static void putNonNull(JsonObject ret, String key, String value) {
        if (value != null) {
            ret.addProperty(key, value);
        }
    }
Encodes the given binaryData in a format that is compatible with the Docker Engine API.
That is, base64 encoded, padded, and URL safe.

@param binaryData data to encode
@return encoded data
src/main/java/io/fabric8/maven/docker/access/AuthConfig.java