Move Icecast password to secrets.liq, remove from tracked files

radio.liq

@@ -4,6 +4,8 @@
 # Tracks, announcements, and jingles are all baked into playlist.m3u
 # Liquidsoap just plays it sequentially.
 
+%include "secrets.liq"
+
 set("log.file.path", "/var/lib/radio/radio.log")
 set("log.level", 3)
 set("server.telnet", true)
@@ -61,7 +63,7 @@ output.icecast(
   %mp3(bitrate=192),
   host="localhost",
   port=8910,
-  password="REDACTED",
+  password=icecast_password,
   mount="/stream",
   name="Radio Susan",
   description="Personal radio station",