Add monthly stats how much tests completed/failed etc.

[qarmin]

I like rust codegen reports which shows how big progress happened in recent month.
https://blog.antoyo.xyz/rustc_codegen_gcc-progress-report-15

E.g.
Test passing

Month	Python version	Passed	Failed	Ignored
February 2022	3.9	2020	1224	1445
March 2022	3.9	2025	1222	1441
April 2022	3.10	2045	1210	1440

[youknowone]

That's a good idea.
We have a dashboard https://rustpython.github.io/pages/regression-tests-results.html
And we also have history of the data https://github.com/RustPython/rustpython.github.io/commits/master

We only need aggregated interface of them to achieve it.