Give a possibility to write custom bet strategies

[KamushekDev]

Is your feature request related to a problem? Please describe.
I found that presented betting strategies aren't enough for me.

Describe the solution you'd like
I would like to have the possibility to provide a custom decision-making function to the BetSettings object. I imagine that function smth like (BetContext context) => BetDecision. Where BetContext contains all necessary information about a bet and BetDecision represents a decision like

{
  result: BetDecisionResult (BET_1, BET_2, BET_3, DONT_BET)
  amount: int
}

Describe alternatives you've considered

• It could be made by changing the source code, but it would cause trouble with updates and could be damaging :c
• Adding every betting strategy from pull requests is working but pretty messy approach. It would bloat strategies with some specific things in the long run.

Additional context
I didn't think over what information should be in a BetContext, but I assume there should be all available information.

[KamushekDev]

Maybe even allow redirect to built-in strategy as a decision.

[1v]

#172

[KamushekDev]

#172

It's a PR for adding another strategy but this issue targets a more generic approach.