Add Vesper (VSP) tokens

[matthewh86]

Need to add support for Vesper (VSP) tokens.

https://app.vesper.finance/

• VSP - 0x1b40183efb4dd766f11bda7a7c3ad8982e998421
• vVSP - 0xbA4cFE5741b357FA371b506e5db0774aBFeCf8Fc
• vDAI - 0xcA0c34A3F35520B9490C1d58b35A19AB64014D80
• vETH - 0x103cc17C2B1586e5Cd9BaD308690bCd0BBe54D5e
• vLINK - 0x0a27E910Aee974D05000e05eab8a4b8Ebd93D40C
• vUSDC - 0x0C49066C0808Ee8c673553B7cbd99BCC9ABf113d
• vWBTC - 0x4B2e76EbBc9f2923d83F5FBDe695D8733db1a17B