profiles: fix application

moving to a DB meant empty slices in the Configuration & Policy structs
were being stored as null, and striking a nerve with Jellyfin.
Mediabrowser library change fixed that by de-nulling them itself, and a
new bool field called "Homescreen" is now used to decide if a profile
has a homescreen layout stored or not. This field is hopefully correctly
filled in during migration.

discord.go

@@ -222,7 +222,6 @@ func (d *DiscordDaemon) NewTempInvite(ageSeconds, maxUses int) (inviteURL, iconU
 	}
 	// FIXME: Fix CSS, and handle no icon
 	iconURL = guild.IconURL("256")
-	fmt.Println("GOT ICON", iconURL)
 	return
 }