Vscode: List/tree: Support setting to set keyboard navigation to toggle model

[joaomoreno]

Similar to listAutomaticKeyboardNavigation contextkey, but as a setting.

[evenfrost]

Another reason it would be great to have such option is that Vim navigation is currently broken with this feature.

[joaomoreno]

VIM navigation is independent of this. It works on startup, but stops working as you switch viewlets around. More info on https://github.com/VSCodeVim/Vim/issues/3466#issuecomment-465481730. Fixed by https://github.com/Microsoft/vscode/commit/5e54b2574b0703aa9437363294f8fd2db63f3e10.

[joaomoreno]

Verification:

1. Set setting workbench.list.automaticKeyboardNavigation to false
2. Verify that filtering in the tree no longer works until you
3. Create a keybinding for the list.toggleKeyboardNavigation command and
4. Press that keybinding

Once you press it, there's no UI feedback, but you can start typing to highlight/filter a tree. Once you Escape or clear the highlight/filter, you have to use the keybinding once more to highlight/filter once more.

[controversial]

When will this feature land?