Handle withdrawal with eth address

[torztomasz]

Resolves L2B-795

[linear]

L2B-795 Handle vaults that use EthereumAddress as StarkKey

On the new Spot StarkEx (and Perpetual v2!!! like Apex?!), assets ready for withdrawal are transferred to a special vault which is assigned to StarkKey that is actually a lot of zeros and an Ethereum address. See this link for details:

<https://docs.starkware.co/starkex/spot/withdrawal.html>

See point 2.

Research if we are handling this correctly. Some idea:

• when displaying user page, we should also check for assets in the vault corresponding to their registered address, otherwise quick actions won't show!?
• as above, we won't be showing regular withdrawals as they are happening on the other vault

Notes:

Use testnet to check how it all works: https://testnet.pro.apex.exchange/trade/