Add tags support for S3 objects

[LouisGarret]

Hello,

Problem: We can't add tagging on S3 objects from configuration. :worried:

Solution: I add the tag's config in knp_gaufrette.yml. :smile:

Ex:

• Input:

  adapters:
  document_adapter:
    aws_s3:
      service_id: ''
      bucket_name: ''
      options:
        create: false
        directory: ''
        tags: 
          key: 'value'
          public: 'yes'

I have also open a pull request on Gaufrette to add support for tags. https://github.com/KnpLabs/Gaufrette/pull/651

@Nyholm

Have a great day! :sun_with_face: