Save all uploads to MFS (via ipfs.files API)

[lidel]

Part of UX improvements for sharing local files (#342)

Current behaviour

Right now upload via right-click context menu or browser action menu item adds raw data to IPFS and it is up to user to memorize or save CID.

Feature Description

Would be great to let user manage shared files via WebUI's Files screen.

Given discussion in ipfs/ipfs-gui#10 (comment):

• when file is uploaded via browser extension it should be automatically added to MFS, so that user can later go back to it or decide to "unpin" it by removing it from MFS.
  • Maybe something like /ipfs-companion-uploads/YYYY-MM-YY_HHMMSS?
  • OR, show a checkbox below (checked by default) saying "Add to My Files at /some/path/" where the default path from Preferences can be chaged inline with super fast autocomplete

References

• pin labels Support optional labels for local pins kubo#4586
• Design: Pinning Content [META] Solidify mental model/language for MFS add vs IPFS pin ipfs-gui#10 (comment)
• Moving away from current pin system Moving away from current pin system kubo#4763
• Context actions should add to MFS Context action to "Add to MFS" #635