docs: Capabilities page - Images can store file-based capabilities

https://dockerlabs.collabnix.com/advanced/security/capabilities/

https://github.com/collabnix/dockerlabs/blob/962fab827c2fb7b8b6149f3d3241cddde0479353/advanced/security/capabilities/README.md?plain=1#L37

https://github.com/collabnix/dockerlabs/blob/962fab827c2fb7b8b6149f3d3241cddde0479353/advanced/security/capabilities/README.md?plain=1#L281

These are inaccurate. The limitation was removed with BuildKit / buildx IIRC which has been the default image builder since Docker 23 (released Feb 2023), which can preserve extended file attributes.

I believe the main issue prior was that you'd lose the extended attributes via a COPY but they would otherwise remain intact so long as the image layer was on a file system that supported the file attributes? (I recall an issue with AUFS, which may still be problematic for some NAS systems)