[data grid] Add separate render method for aggregation row

[Vagizova]

Summary

So when you use custom aggregation functions, you will most likely have to add renderCell, check if it is an aggregation row or not, etc. but in this case you are actually using renderCell for every cell, although it is only needed for one row. Using this in every cell significantly reduces the performance of the table as a whole

We have a large table, hundreds of rows by hundreds of columns. so this significantly reduces the performance. We have already applied all the tips from the page

how about having something like separate aggregationCellRender on column def lvl? so we can render value in each

if it is not possible, it would be grate you can explain why and how i can avoid performance issue

Motivation

let's optimize as many places in this table as possible, i really want to use your product, but right now it doesn't seem possible

Search keywords: aggregation footer render

[Vagizova]

Another finding: Is it possible to set Height to aggregation row separately? why? because I have to do something like that:

const getRowHeight = useCallback(
    ({ id }) => (id === 'auto-generated-group-footer-root' ? 'auto' : undefined),
    [],
  );
  

and this worsens performance even more than what is described above

[michelengelen]

Might be worth exploring ... the findings make sense, even if we provide an optional override with the default set to the cellRenderer. I would call it renderAggregationCell though, just to be consistent with the naming! 👍🏼

I'll add this to the board as a feature request!

Thanks for opening this @Vagizova