* feat: add sway-mode module
* refactor: Avoid making multiple connections to SwayIPC
Now `sway::Client` is store in `ironbar.clients`, and allow dynamically
registering event listeners, instead of hardcoding events for Workspace
updates.
Remove the use of `swayipc::Connection` from `sway-mode` module, and
replace it with the new event listener system.
#671
