v1.25.0 - Jebudo (제부도, 濟扶島)

Raw client and support of NeoFS API v2.5.0 "Jebudo" release.

Added

• Raw client for peer to peer communication.
• client.WithKey option to sign messages with different keys within single
  client.
• Content-Type well-known object attribute constant.

Changed

• Refactored v2 sub-packages to support single raw client in all RPC methods.
• Client constructor returns Client interface instead of structure.