Remove prioritization_fee.rs

[ksolana]

The prioritization_fee.rs had only one relevant calculation of
prioritization fee that was used by ComputeBudgetLimits. This patch moves the calculation to get_prioritization_fee and removes prioritization_fee.rs altogether.

[apfitzge]

are the other methods used? if the compute unit price isn't used then I feel this trait is useless and we should remove the whole thing.

[tao-stones]

Agree, it's the time to refactor out PrioritizationFeeDetails since enum PrioritizationFeeType has been reduced to one variance, the legacy logic of converting between user specified priority fee and cu price has gone - now transactions can only specify cu price. So all PrioritizationFeeDetails does is prio-fee = cu-price * cu-limit, which can be done inline in ComputeBudgetLimits, where FeeBudgetLimits are created.

[tao-stones]

changes look good to me - thanks for cleaning it up.

[apfitzge]

please update title of the PR and add a basic description to the PR

[tao-stones]

lgtm