function startRestore(objectMD, restoreParam, log, cb) {
    log.debug('Validating if restore can be done or not.');
    const checkResultError = _validateStartRestore(objectMD, log);
    if (checkResultError) {
        log.debug('Restore cannot be done.', {
            error: checkResultError,
            method: 'startRestore'
        });
        return cb(checkResultError);
    }
    const updateResultError = _updateRestoreInfo(objectMD, restoreParam, log);
    if (updateResultError) {
        log.debug('Failed to update restore information.', {
            error: updateResultError,
            method: 'startRestore'
        });
        return cb(updateResultError);
    }
    log.debug('Validated and updated restore information', {
         method: 'startRestore'
    });
    const isObjectAlreadyRestored = _updateObjectExpirationDate(objectMD, log);
    return cb(null, isObjectAlreadyRestored);
}
start to restore object.
If not exist x-amz-restore, add it to objectMD.(x-amz-restore = false)
calculate restore expiry-date and add it to objectMD.
Be called by objectRestore.js

@param {ObjectMD} objectMD - objectMd instance
@param {object} restoreParam - bucket name
@param {object} log - werelogs logger
@param {function} cb - bucket name
@return {undefined}