ERC-5095 Principal Token

StagnantERCcreated 2022-05-01requires ERC-20, ERC-2612

Principal tokens (zero-coupon tokens) are redeemable for a single underlying EIP-20 token at a future timestamp.

Authors: Julian Traversa (@JTraversa), Robert Robbins (@robrobbins), Alberto Cuesta Cañada (@alcueca)

Functions this standard introduces (10)

`0x25a8d87d`	`convertToPrincipal(uint256)`	view
`0x1dc7f521`	`convertToUnderlying(uint256)`	view
`0x204f83f9`	`maturity()`	view
`0xd905777e`	`maxRedeem(address)`	view
`0xce96cb77`	`maxWithdraw(address)`	view
`0x4cdad506`	`previewRedeem(uint256)`	view
`0x0a28a477`	`previewWithdraw(uint256)`	view
`0xba087652`	`redeem(uint256,address,address)`
`0x6f307dc3`	`underlying()`	view
`0xb460af94`	`withdraw(uint256,address,address)`

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

0xd12200efa34901b99367694174c3b0d32c99585fdf37c7c26892136ddd0836d9 Redeem(address,address,uint256)

Proposals this one names in its requires field.