Create a page that aggregate all the key settings from all addons

[wengxt]

So it has been an issue that user unable to figure out what key is being occupied.

Ideally we can have a centralized tab that shows all hotkey being configured.

Right now I have a few different ideas for this.

1. Create an separate addon or add a new dbus uri, and let it scan through all the addon config.
2. Do the same thing on the configtool side.

I do also hope that the hotkey config can be organized in a better way, unlike the normal config page, but like kde’s global hotkey UI.