[polybar] Use bib-due date filter

Utilize the date filter option to display upcoming readings until the
end of the week and no further. Needs gnu date utility.

polybar/.local/bin/polybar-launch

@@ -1,4 +1,6 @@
 #!/usr/bin/env bash
+# force start or restart (all) polybar instances
+# if ipc is enabled, can be replaced with `polybar-msg cmd restart`, provided polybar is not stuck
 
 # Terminate already running bar instances
 killall -q polybar