Add option to allow empty password or not (closes #577)

Signed-off-by: AnErrupTion <anerruption@disroot.org>

res/config.ini

@@ -15,6 +15,9 @@
 # special value 0x00000000. This means that, if you want to use black, you *must* use
 # the styling option TB_HI_BLACK (the RGB values are ignored when using this option).
 
+# Allow empty password or not when authenticating
+allow_empty_password = true
+
 # The active animation
 # none     -> Nothing
 # doom     -> PSX DOOM fire