[ABIP-10] Allow pabi redemption to ABI and Lock

Summary

Allow swapping of pABI for ABI at 1:1 & lock for three years.

Abstract & Motivation

A few pABI holders have requested to lock their pABI allocation for the entire three years in return for not having to pay the backing per pABI.

The price of ABI is below backing currently and for pABI holders. This does not give them any incentives to provide the backing. We would like to give each pABI holder the option to convert their entire pABI allocation to ABI and have it locked for three years via a smart contract.

No changes will be made to the liquidity currently provided for pABI holders to exit at ~$1.5 (uniswap) and no changes will be made for holders who do not wish to convert the pABI, they will still be able to provide the backing and convert pABI to ABI.

This allows a lot of holders to align with the long term without the daily price action.

Methodology

To facilitate this, the team will write a small contract that takes pABI and mints new ABI and places them in a lock vault. The ABI minted will also be staked so that after the three years are up the holders will receive ABI and any stakes emissions.

Eligibility

Only whitelisted pABI holders will be eligible. Those buying at the uniswap pool or who are not on the original pABI purchasers list will not be eligible.