Better window attributes icons in polybar

[DrPyser]

bspwm window state and flags are shown in polybar, to the right of the workspaces.
Currently, they are shown as letters:

configs/home/.config/polybar/config

Lines 134 to 146 in c71f98f

	label-monocle = M
	label-tiled = T
	label-fullscreen = F
	label-floating = f
	label-pseudotiled = Pt
	label-locked = L
	label-locked-padding = 1
	label-locked-foreground = #bd2c40
	label-sticky = S
	label-sticky-foreground = #fba922
	label-private = P
	label-private-foreground = #bd2c40
	label-marked = m