[Features] Floating window feature, ignore hotkey capturing, etc

[gkzhb]

Glad to see there is such a powerful open-source project that provides similar functinalities with i3wm in Windows. It's very useful for me to achieve keyboard-only navigations in Windows. Using it happily for some time, I get some questions and requests.

1. Compared with i3wm, I can see that we don't have floating window mode and scratchpad which I think may be useful. Sometimes I want to minimize a window temporarily, which cannot be achieved directly now though I can move it to other workspaces.
2. When playing games (like Genshin Impact in window mode), I add the game to 'windows_to_ignore' list. But the hotkeys containing mod key (alt) are all captured and cannot be sent to the game. Therefore, I wonder if we can ignore hotkey capturing for 'windows_to_ignore'.
3. Wish to allow to define more custom commands like 'start_command' which acts like exec in i3wm. For the json config file, now we are assigning hotkeys to the keys that map to the functionalities. Can we exchange the mapping order and allow to assign multiple hotkeys to one functionality which I think may be a better way to add more custom commands for users.

Thanks for your time.