Add uVIX, uSPY price identifiers PERPETUAL

Synthetic tokens that track the exchange quotes of the volatility index (VIX) and the S&P exchange traded fund (ETF SPY) can be used both for speculative purposes and for hedging. At the same time, the user gets the opportunity to use the price movement of exchange assets without the need to use such centralized structures as exchanges and brokerage companies. In addition, these tokens can be used as components associated with classical markets by other DeFi and DApp protocols, which makes it possible to scale.