Initial full version of the vault

A vault is an entity that takes as input:
- some amount of ERC-20 tokens
- Policy on how to distribute it between the available strategies

Its functions include several things:
- distributes the tokens according to the given policy
- withdraws the tokens from the strategy when requested
- When a slashing event inside one of the strategies happens, it produces a slashing event and slashes the corresponding share of itself. The Collateral Abstraction watchtower keeps track of the slashing events and propagates them according to the protocol

In the first production version of the Collateral Abstraction, we will use a simple vault that has two groups of strategies: Symbiotic and Eigenlayer. Each group might be represented by one or more vaults, which differ by risks and yield.