Coinex fetchTrades
Coinex fetchTrades

Added swap functionality to fetchTrades:
```
coinex.fetchTrades (BTC/USDT:USDT)
2022-04-25T20:35:04.840Z iteration 0 passed in 294 ms

    timestamp |                 datetime |        symbol |        id | order | type | side | takerOrMaker |    price | amount |        cost | fee | fees
--------------------------------------------------------------------------------------------------------------------------------------------------------
1650918885557 | 2022-04-25T20:34:45.557Z | BTC/USDT:USDT | 382747754 |       |      | sell |              | 40122.27 | 0.0594 | 2383.262838 |     |   []
1650918893592 | 2022-04-25T20:34:53.592Z | BTC/USDT:USDT | 382747919 |       |      |  buy |              | 40122.28 | 0.0074 |  296.904872 |     |   []
1650918898610 | 2022-04-25T20:34:58.610Z | BTC/USDT:USDT | 382747965 |       |      |  buy |              | 40122.28 | 0.0469 | 1881.734932 |     |   []
3 objects
```

ccxt/ccxt,ccxt/ccxt,ccxt/ccxt,ccxt/ccxt,ccxt/ccxt