feat: add support for billboard role in startup script

autorun/startup.lua

@@ -28,6 +28,8 @@ elseif cfgExists('.webbridge_config') then
     role = 'bridge'
 elseif cfgExists('.miner_config') then
     role = 'miner'
+elseif cfgExists('.billboard_config') then
+    role = 'billboard'
 elseif _G.turtle then
     role = 'turtle'
 end
@@ -72,6 +74,7 @@ local programs = {
     bridge    = 'inventoryWebBridge.lua',
     turtle    = 'craftingTurtle.lua',
     miner     = 'miningTurtle.lua',
+    billboard = 'monitorBillboard.lua',
 }
 
 local program = fs.combine(BASE, programs[role])