Spans are added only to the following middleware:
* PolicyCheck
* Auth
* FrostfsIDValidation
This is done this way because these middleware are basic and
they interact with frostfs-storage.
Also, an explicit context has been added to many functions
so that the middleware spans do not include all subsequent spans.
Signed-off-by: Roman Loginov <r.loginov@yadro.com>
Use `UNSIGNED_PAYLOAD` to check signature if x-amz-content-sha256 isn't provided as signed header
https://docs.aws.amazon.com/AmazonS3/latest/API/sig-v4-header-based-auth.html
" You include the literal string UNSIGNED-PAYLOAD when constructing a canonical request, and set the same value as the x-amz-content-sha256 header value when sending the request to Amazon S3"
Signed-off-by: Denis Kirillov <d.kirillov@yadro.com>
