Implement metrics aggregations

[buinauskas]

No description provided.

[iamazy]

Can you assign it to me? I'm willing to provide support！

[buinauskas]

@iamazy totally! Try submitting changes in smaller batches if possible, they'll be easier to review. Let me know if you have some questions, I'll be glad to answer them.

Thank you very much!

[iamazy]

• cardinality(Implement cardinality aggregation #29)
• avg(Implement avg aggregation #34)
• max(Implement metrics aggregations #35)
• min(Implement metrics aggregations #35)
• sum(Implement metrics aggregations #35)
• rate(Implement rate aggregation #37)
• boxplot(Implement Boxplot aggregation #39)

[iamazy]

@buinauskas Hi, I submit a pr(#29) and you can see if there have any problem. I will submit pr just like that later.

[buinauskas]

@iamazy that's excellent!

[buinauskas]

@iamazy I just want to appreciate and thank you for all the work you've put into implementing aggregations/queries for this project. You're doing an amazing job, thank you!

[iamazy]

@buinauskas That's all right, I also learned a lot from this project!