Add minio support by adding 'use_path_style_endpoint' to configs

Minio is alternative s3 compatible self-hosted service. This is a really nice alternative for s3 in local development.

I got local minio fileserver working with flysystem_s3 today by using 'use_path_style_endpoint' => 'true' in the parameters for Aws\S3\S3Client in AWS PHP SDK.

Could you please add this parameter into the possible configurations in settings.php?

Source: https://github.com/minio/cookbook/blob/master/docs/aws-sdk-for-php-with-...
More info on minio: https://minio.io/