Better global pane selector

[simonmandlik]

It would be great to have something like tmux choose-window or choose-tree in Wezterm. A selector that would make it possible to

1. get quick overview of everything that is opened
2. quickly switch to any pane

Currently, AFAIK we have

• PaneSelect to select pane within active window,
• ShowTabNavigator for switching tabs, and
• ShowLauncherArgs for tabs and/or workspaces.

but no unified selector for panes, tabs, windows and workspaces