Implementation of swaywm/wlr-protocols#35
Depends on: swaywm/wlr-protocols#35 and swaywm/wlroots#2357

What works:

• Enumeration of enabled workspaces
• Activate request

What almost works:

• Coordinations setting. I set them in order_output. But this method is not triggered by every workspace creation/destroy.
  So behavior is inconsistent. Need to find right place to set coordinates

What need to rework:

• workspace_group is created for each output. There is need to extend config to support other cases such one group for each outputs