Implement x-amz-tagging support

[Climax777]

Please implement the tagging feature of s3 https://docs.aws.amazon.com/AmazonS3/latest/API/RESTObjectPUT.html

The header is: x-amz-tagging and is key-value encoded like most header stuff.

[kherock]

I'll take a look at this soon. This should be simple to implement, no one has asked for it until now!

[fishcharlie]

If I can find time this weekend going to see if I can work on implementing this.

[fishcharlie]

I'm super confused about this issue. Should this even still be open?

As @kherock mentioned in this comment: #591 (comment), there is a test that covers this use case.

[kherock]

@fishcharlie you might be confusing this with x-amz-meta-* support. Tagging is stored separately from meta and is only shown in the ?tagging endpoints for buckets an objects. More documentation is available here.