This modifies `bar_cmd_bindsym` to use `get_mouse_bindsym` for parsing
mouse buttons. This also introduces `cmd_bar_bindcode`, which will use
`get_mouse_bindcode` for parsing mouse buttons. Like sway bindings, the
two commands are encapsulated in a single file with shared code.
This also modifies swaybar to operate off of event codes rather than x11
button numbers, which allows for any mouse button to be used.
This introduces two new IPC properties:
- For `get_bar_config`, `event_code` has been added to the `bindings`
section and will include to event code for the button. If the event code
can be mapped to a x11 button, `input_code` will still be the x11 button
number. Otherwise, `input_code` will be `0`.
- Likewise for `click_events`, `event` has been added and will include
the event code for the button clicked. If the event code can be mapped
to a x11 button, `button` will still be the x11 button number.
Otherwise, `button` will be `0`.
