Introduced /exchanges/{id}/volume_chart

We have added a new endpoint, /exchanges/{id}/volume_chart.

This endpoint is designed to provide volume chart data related to the specified exchange, with the information presented in BTC.

Example of responses:

[
  [
    1707030000000,
    "141206.9308600928467152" 👈 value in BTC
  ],
  [
    1707030600000,
    "141639.1493761186305005" 👈 value in BTC
  ],
  ......
 ]