Add BitMart Futures Market

[Jasper7619]

Describe your environment

(if applicable)

• Operating system: ____
• Python Version: _____ (python -V)
• CCXT version: _____ (pip freeze | grep ccxt)
• Freqtrade Version: ____ (freqtrade -V or docker compose run --rm freqtrade -V for Freqtrade running in docker)

Describe the enhancement

Explain the enhancement you would like Currently only BitMart spot trading is available, but BitMart also provide futures trading