Add ERC: Content encoding in ERC-5219 mode Web3 URL

[nand2]

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[eip-review-bot]

✅ All reviewers have approved.

[nand2]

I have modified the contents to take into account Sam's point : if the compression of the returned data is advertised by the client in accept-encoding, then decompression by the protocol is not necessary. It is only necessary when the client does not advertise decompression capabilities for the compression of the returned data.

[nand2]

And thanks for your review @SamWilsn !