ERC-6808 Fungible Key Bound Token

FinalERCcreated 2023-03-31requires ERC-20

An interface for Fungible Key Bound Tokens, also known as a FKBT.

Authors: Mihai Onila (@MihaiORO), Nick Zeman (@NickZCZ), Narcis Cotaie (@NarcisCRO)

ERC-165 interface ids

Computed here as the XOR of the selectors each interface defines.

IKBT20 0xcc6323b1

`0xe54e193c`	`addBindings(address,address)`
`0x9abb7c91`	`allowApproval(uint256,uint256)`
`0x7c9dc1a7`	`allowTransfer(uint256,uint256,address,bool)`
`0x20fb3be3`	`getApprovalConditions(address)`	view
`0x0e020296`	`getBindings(address)`	view
`0x3e794dc0`	`getNumberOfTransfersAllowed(address,address)`	view
`0x2a440d98`	`getTransferableFunds(address)`	view
`0xecbb669f`	`isSecureWallet(address)`	view
`0x7d1a5bd1`	`resetBindings()`
`0x646ec3d8`	`safeFallback()`

Topic0 is the keccak256 hash of the signature, which is what a log filter matches on.

`0x5807519689a5040d7de09b89689f6b12321ddcee52699d8bb864f4363b8a4220`	`AccountSecured(address,uint256)`
`0x3936b7c77a600cb259c805bd725ee2098b2c99c27a76744d697003aaa5dbc931`	`AccountResetBinding(address)`
`0x25a2abf52609ac61e3adb8b5b4d53d328d7abb17b8aee9b7b463f4ebedbbca1d`	`SafeFallbackActivated(address)`
`0x69fcc0e8657da8baee763cbf800b20425094596b4de6dcd49c190d9eed61bdb7`	`AccountEnabledTransfer(address,uint256,uint256,address,bool)`
`0x5aa44865b966bd9a28e3e814cea0105560fc32a8b8da3e2ce3424e518ea36113`	`AccountEnabledApproval(address,uint256,uint256)`
`0x1841f6b59753ea5f4490c3d74fe8b30c348b0a8f7c3b5ea14ae72e52a04060a4`	`Ingress(address,uint256)`
`0xa9414721b1240ec5c4c6d0f51cf9315b9ae71bcd5a654ce3d88a1534878893e0`	`Egress(address,uint256)`

Proposals this one names in its requires field.