Markets - Update schema and parsers

[arboleya]

We need to add to new properties on the market schema:

• minTradeAmount ^(*)
• maxTradeAmount

^(*) This one exists inside the market.instrument sub-schema, from which it should be removed.

These properties will require minor parsing adjustments on the market parser for all exchanges:

• Bitfinex
• Bitmex
• Bittrex
• Binance
• Gate
• Poloniex
• Valr
• FTX

The ongoing PRs for OKX and Huobi must also implement this.

cc @LucianoPierdona

[arboleya]

@Torres-ssf Do you see any complications regarding this issue?

[Torres-ssf]

@arboleya I reckon these props should be optional, I'm almost sure not all exchanges are providing this info