TZIP-029: Etherlink token bridge

Hello there!

This standard outlines the bridging protocol stack for transferring Tezos assets to and from the Etherlink smart rollup.

The document details the token bridging protocol stack, including API specifications, semantics, and security considerations for developers. It aims to facilitate the adoption of the bridging protocol, fostering Etherlink usage and increasing liquidity on L2.

Etherlink, an optimistic EVM rollup on Tezos, seeks to enhance blockchain user experience by facilitating liquidity through asset bridging from Tezos L1. The standard supports native token bridges, bridges for liquid L1 tokens, and a generic bridging protocol, promoting Etherlink adoption and liquidity on L2.