code: function _buildUrl (config, type, multi) {
    let url = config.url
    let language = _getLanguage(config.language)
    let block = multi ? config.blocks[type][language] : config.blocks[type]
    let version = _getVersion(config.version)
    return `${url}${block}?v=${version}&l=${language}`
  }
docs: Build API url to Cortins from where to retrieve the blocks.
  @param {*} config the given config
  @param {*} type the block type eg. image
  @param {*} multi