[Improvement] MAXIMUM_BUY_AMOUNT_IN_BASE_PER_COIN

[AdamB2023]

We've MAXIMUM_BUY_AMOUNT_IN_BASE, but it only applies to a single transaction. With BUY_SEVERAL_TIME_SAME_TOKEN : true we are risking being drained. Having an MAXIMUM_BUY_AMOUNT_IN_BASE_PER_COIN would allow us to mitigate it.