FIXME: allow multiple files in content

[milahu]

currently, content can hold only one file, usually utf8-encoded text.

it would be nice to send multiple files per event, for example:

• text with images
• text with video
• video with subtitles
• arbitrary folders of files

benefits:

• avoid sending images as base64
• reuse one image in multiple places
• avoid muxing streams into one video file
• avoid workarounds like zip-archives

this would make nostr more similar to bittorrent/zeronet/twister

[dr-orlovsky]

I think multiple files can be packed as a tar package

[milahu]

at least we should add a content type, so users can describe the payload type.
how about:

• enum values from 1 to 255 = some commonly used mimetypes:
  • text/markdown; charset=utf8
  • text/html; charset=utf8
  • application/zip; charset=binary
  • application/tar; charset=binary
  • application/tar; charset=binary+application/gzip; charset=binary
  • application/x-7z-compressed; charset=binary
• value 0 + length-prefixed utf8-string (max 255 bytes length) = custom mimetype

[dr-orlovsky]

I am not a big fan of something non-standard; the selection of 255 "common" types looks too opinionated for me...

We can allow MIME / MediaType in string representation - that is better (in binary serialization the string prefixed with one byte length).