Adding Secure Files to Object Storage Docs

What does this MR do and why?

Adds uploader details for the Secure Files features to the object storage docs page.

@mkaeppler thanks for the ping in https://gitlab.com/gitlab-com/gl-infra/infrastructure/-/issues/15096. I believe I've added the necessary details to the tables, but please let me know if I've missed anything. For reference here are the model and uploader files for this feature:

• Model: https://gitlab.com/gitlab-org/gitlab/-/blob/master/app/models/ci/secure_file.rb
• Uploader: https://gitlab.com/gitlab-org/gitlab/-/blob/master/app/uploaders/ci/secure_file_uploader.rb

Also, I wasn't sure what Categorized was for, so I left it blank.

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