Generate confidence interval with bootstrap

As shown in: https://lmsys.org/blog/2023-12-07-leaderboard/. I think this function will be useful and convenient in practice. But I'm not sure if it's appropriate to add it to evalica. I think evalica is very consice and focus on core computation of the algorithms, which is good enough currently. If it's not appropriate, I'll try to build a simple python package based on evalica to add this functions, maybe will more visualization functions(as shown in the jupyter notebooks) too.