add Data Table tree view

Is your feature request related to a problem? Please describe.
Currently there's no tree visualisation for a pivot table (like in Excel). It's a really neat layout that allows lazy and partial exploration of the data.

Describe the solution you'd like
A data table capable of (partially and fully) collapsing and expanding the data as if it was a tree.

Describe alternatives you've considered
Using pandas, active_cell and dcc.Store (to keep track of odd/even clicks) to pivot/un-pivot and filter data on cell click.

Additional context
Excel Tree Layout

Non vengono indicati file, test o punti di ingresso. Inizia individuando l’implementazione esistente di Data Table e pivot-table, quindi determina come vengono rappresentate e renderizzate le righe o colonne raggruppate. Il lavoro è completo quando la tabella supporta sia il collasso e l’espansione parziali sia quelli completi in un layout ad albero, come descritto nell’issue.