Feature: Add TreeView

[rc1]

Important

Please note, this GitHub issue is keeping track of two separate but related features. A Tree View sidebar, and a Tree View layout. Both are features we're planning to implement, but they are currently blocked until we make further gains in the performance area. Please see #1928 (comment). We encourage the community to contribute performance enhancements, which, aside from the obvious benefits, will also enable us to proceed with these features.

Is your feature request related to a problem? Please describe.

Typically, I work in a project folder. That folder might have multiple sub folders like: images, src, prints, presentations. With Windows Explorer and Files, I must keep navigating in and out of folders. I want a view of all my files and folders in one view. Much like how VS Code's 'Explorer' handles files display and navigation, or how Mac's Finder handles.

Describe the solution you'd like

In list view, I'd like a tree navigation component for files allowing me to expand a folder to list is child files and folders (which can be expanded too)

Describe alternatives you've considered
None. I've tried for years now without this feature on Windows. Still miss it sorely from Mac.

Additional context
There is discussion on Reddit where someone looks for this feature on Windows.

Here is a found image of Finder on Mac.

[issue-label-bot]

Issue-Label Bot is automatically applying the label feature_request to this issue, with a confidence of 0.92. Please mark this comment with 👍 or 👎 to give our bot feedback!

Links: app homepage, dashboard and code for this bot.

[mdtauk]

In case this is looked at again, here is a mock-up for how it could be implemented

The drop down would allow the picking of a drive

-treeview in sidebar helps to quickly move files b/w folders.
-helps with quick navigation like if i am in X folder and want to open Z folder without the need to open a new tab or dual pane (as dual-pane will take screen space)
-also if needed can perform actions like open in new window or open in new tab or in 2nd pane or open terminal in a certain folder from the sidebar
-if we only have sidebar support then we will have to pin a folder for quick action and it will clutter the sidebar

[mdtauk]

Despite my previous mockup showing a TreeView alongside the Sidebar, toggling between the two would work better, with only the favourites being shared between both options.