Image Rehosting via HTTP API

[lidel]

Shower idea: right click on ANY image and get its IPFS address ✨

• This is similar to Rehost on ipfs.pics ipfspics/ipfspics-server#7 but does not require any third party service
• Addon would upload image (already downloaded by the browser) to the API and open IPFS mirror in a new tab (local or public, depending on the redirect status)
• Probably will use /api/v0/add with multipart encoding
  • This may be a good moment to add js-ipfs-api as a dependency (browserified if necessary) (see Reuse js-ipfs-api as IPFS HTTP API client #151)
  • Code samples for blob upload: Create example: uploading binary file via browser form "file upload" ipfs-inactive/js-ipfs-http-client#316
• There should be an option (disabled by default) to:
  • automatically Pin such images
  • asynchronously do HTTP HEAD request to a customizable list of public gateways (to solve the coffee shop problem: someone rehosts the image, sends it to someone else and then goes offline leaving receiver without any seeds).
  • customize URL opened after upload, probably in a form of substitute mask:
    eg https://yt.aergia.eu/#i=%hash% (IPFS Support lidel/pls.watch#145)

References:

• SDK: context-menu#SelectorContext