SNIP-XXX Tokenized Vault standard (EIP-4626)

[nbundi]

This PR introduces a new standard for "tokenized vaults".

The standard is inspired by EIP-4626, a standard that has found wide adoption on EVM chains.

Tokenized vaults are a common pattern across DeFi and Starknet. E.g. Nostra, zkLend, Nimbora and others use variations of tokenized vaults. Similar to EIP-20, this standard unlocks greater composability, efficiency and security around implementations and derivative work.