[Feature] Support virtual host S3 API calls

先閱讀 localstack_client.config.get_endpoint 和 get_service_endpoints，接著使用 boto3 偵錯記錄和 Docker Compose 重現 S3 請求。檢視 README.md 中的 endpoint 指引，並判斷專案應採用所提出的三種方法中的哪一種；done 應包含一條已決定且可正常運作的 virtual-host addressing 路徑，以及相應的文件。

After struggling for several hours with Docker Compose, I noticed my problem was actually in this library, which does not seem to support the virtual host addressing for the s3 client.

Looking at boto3 in debug mode, I noticed that when using Virtual host addressing, the HTTP request was aimed towards http://<bucket>.<endpoint_url>:<endpoint_port>. This is not a valid endpoint, and it should be http://<bucket>.s3.<endpoint_url>:<endpoint_port>, as described here.

After delving deeper I noticed localstack_client.config.get_endpoint it is not handling s3 in any special way. I manually patched the function and noticed that with a simple

def new_get_service_endpoint(
        service: str, localstack_host: Optional[str] = None
    ) -> Optional[str]:
        endpoints = localstack_client.config.get_service_endpoints(localstack_host=localstack_host)
        endpoint = endpoints.get(service)
        if service == "s3":
            endpoint = "http://s3." + endpoint.split("http://")[1]
        return endpoint

I know this doesn't handle SSL, it's just a draft. It works for both virtual and path based addressing.

I see three ways simple about this:

1. Do not support virtual host addressing. This is a problem, as in theory AWS is deprecating path based addressing (also it has been deprecating it for 4 years, so...)
2. Do a hack like the one proposed.
3. Honor AWS service specific endpoints through envars (for instance AWS_ENDPOINT_URL_S3) and leave it up to the user to set it up (with appropriate documentation, at least in the README.md).

What are your thoughts on this?