feat: Add bcd price divisor for ticker

[ranjanrak]

• Add BCD(BSE CDS) price divisor factor for the ticker.
• Add BCD exchange constant for BCD order placement.

[vividvilla]

I don't know why we did this earlier but bsecds should be bcd in the map. Since we export this we can't just rename so we need to add new key called bcd with same value value 6 and add a note about deprecation in next version.

https://github.com/zerodha/pykiteconnect/blob/14fc04e155e6cb11abd2bd4211f1bcb065cd659f/kiteconnect/ticker.py#L366