Implement dynamic betting intervals for long-running markets

[coderabbitai]

As per this comment, @evangriffiths suggested that for long-running markets, we might want to define betting intervals dynamically based on the duration of the market. Instead of using a fixed time interval, consider having max_bets_per_market: int = 10, and check if a timedelta of market_duration / 10 has elapsed since the last bet.

This approach would space out bets uniformly over the market's duration.

PR: #523
Comment: #523 (comment)
Requested by: @kongzii