feat(legacy): trim overbooked shows after autoloading a playlist (#2897)

### Description

Some combination of preload/postload and autoloding playlists with
smartblocks generate massively overbooked shows that clutter up the
interface. This addition performs a 'trim overbooked' after filling up
the autoload list, and does the same as pushing the 'trim overbooked'
button in the UI.


### Testing Notes

Define an autoloading playlist of 2 hours and schedule it for a one hour
show. Without patch, you'll get entries for 2 hours, with the patch, you
only get one hour and a 'overboarding' orange entry at most.

---------

Co-authored-by: Kyle Robbertze <paddatrapper@users.noreply.github.com>
Co-authored-by: Thomas Göttgens <tgoettgens@mail.com>
Co-authored-by: jo <ljonas@riseup.net>

legacy/application/models/Preference.php

@@ -1399,6 +1399,16 @@ class Application_Model_Preference
         self::setValue('radio_page_display_login_button', $value);
     }
 
+    public static function getScheduleTrimOverbooked()
+    {
+        return boolval(self::getValue('schedule_trim_overbooked', false));
+    }
+
+    public static function setScheduleTrimOverbooked($value)
+    {
+        self::setValue('schedule_trim_overbooked', $value);
+    }
+
     public static function getRadioPageDisabled()
     {
         return boolval(self::getValue('radio_page_disabled', false));