function createBase64Url(content, mime) {
  var data;
  var datauri;

  if (typeof content !== "string") {
    // Only handles strings
    return;
  }

  data = btoa(encodeURIComponent(content));
  datauri = "data:" + mime + ";base64," + data;
  return datauri;
}
Create a new base64 encoded url
@param {any} content
@param {string} mime
@returns {string} url
@memberof Core