Adaptive partitioning of trees

[JanKoehnlein]

One thing that really annoys me in the world of JavaScript is the tendency to have hundreds of files / folders at the same level. Even in VSCode, the navigator is a real pain to browse node_modules or get out of there once you opened them by hazard. We could be better with Theia here.

Proposal:
When a tree node has more than a configurable number of children (e.g. 30), automatically add artificial nodes to group them. Show a range of the first distinguishing letters as the name of these nodes and give them an icon / color that marks them clearly as artificial

node_modules
  + (a... - d...)
  + (d... - mate...)
  + (math... - stre...)
  + (stri... - z...)

We could also think about keyboard shortcuts to enable/disable this partitioning.