Simple dwm style status bar

[sminez]

Is your feature request related to a problem? Please describe.
Currently Penrose requires an external status bar (such as Polybar or Lemonbar) and we don't yet fully support all of the EWMH proerties required to make that experience seemless. This also relies on configuring said bar externally and managing it.

Describe the solution you'd like
Ideally we want to have an easy to use / configure bar that makes use of the Hooks system but initially, an inbuilt dwm style bar that is driven by xsetroot would be nice (especially as existing dwm users can re-use their existing set ups). Going forward, I'd like to get my old Qtile bar working again but that'll be quite a bit more work I suspect.

Describe alternatives you've considered
Currently using Polybar which is fine but I want to have something a little more minimal and the build of Polybar in arch has now broken on me twice since I started using it due to external dependencies changing...

Additional details
It would be nice if eventually this can be a stand alone bar that runs without Penrose but that can be extracted at a later date. At that point, moving the bar (and maybe the draw abstraction?) to its own Crate is probably a good idea.

Requirements

• New hook added for when the root window name is updated (to allow for re-render when the user updates from their external process)
• Extract initial low level drawing logic out into a new trait so that it doesn't have to be the default XCB implementation if users don't want it.
• Refactor current dummy implementation from draw to use the new traits
• Simple, default status bar widgets:
  • Workspaces (indicating focused and those with active clients)
  • Focused window title (optional icon / default if not focused etc)
  • Static text

[sminez]

Initial implementation complete as of v0.1.9