function convertToPmCollectionVariables (serverVariables, keyName, serverUrl = '') {
  var variables = [];
  if (serverVariables) {
    _.forOwn(serverVariables, (value, key) => {
      let description = getParameterDescription(value);
      variables.push(new Variable({
        key: key,
        value: value.default || '',
        description: description
      }));
    });
  }
  if (keyName) {
    variables.push(new Variable({
      key: keyName,
      value: serverUrl,
      type: 'string'
    }));
  }
  return variables;
}
Converts the necessary server variables to the
something that can be added to the collection
TODO: Figure out better description
@param {object} serverVariables - Object containing the server variables at the root/path-item level
@param {string} keyName - an additional key to add the serverUrl to the variable list
@param {string} serverUrl - URL from the server object
@returns {object} modified collection after the addition of the server variables