fix(vaults): use batch calls for vaults/all endpoint

[nymmrx]

Discussed in discord PMs.

... a continuation of #50

Short summary:

• added the vaults/all endpoint that returns V1 & V2 vaults, following the format:

[{
   "address": "0x123...",
   "name": "vault name",
   "symbol": "vault symbol",
   "decimals": "vault decimals",
   "type": "v1"
}]

• replaced old calls with a web3 batch call
• added interfaces for vaults