[docs][Grid v2] Restructure docs

[DiegoAndai]

Related page

https://mui.com/material-ui/react-grid2/

Kind of issue

Other

Issue description

The Grid v2 docs structure is somewhat chaotic. We should update it to be closer to Joy's docs: https://mui.com/joy-ui/react-grid/.

Search keywords: gridv2 grid docs

[DiegoAndai]

On hold: https://github.com/mui/material-ui/pull/42742

[danilo-leal]

This should probably be accounted for in https://github.com/mui/material-ui/issues/35158 — wondering if we need this issue... cc @samuelsycamore

[siriwatknp]

This should probably be accounted for in #35158 — wondering if we need this issue... cc @samuelsycamore

Agree, I think this issue is a duplicate.