feat(#99): introduce spot REST client

src/types/spot.ts

@@ -0,0 +1,18 @@
+export type OrderSide = 'Buy' | 'Sell';
+export type OrderTypeSpot = 'LIMIT' | 'MARKET' | 'LIMIT_MAKER';
+export type OrderTimeInForce = 'GTC' | 'FOK' | 'IOC';
+
+export interface NewSpotOrder {
+  symbol: string;
+  qty: number;
+  side: OrderSide;
+  type: OrderTypeSpot;
+  timeInForce?: OrderTimeInForce;
+  price?: number;
+  orderLinkId?: string;
+}
+
+export interface SpotOrderQueryById {
+  orderId?: string;
+  orderLinkId?: string;
+}