Add customizable foreground color to CMatrix (#652)

* Final fixes, adding fg_ini as field

* Capital B changed to lowercase

src/config/Config.zig

@@ -16,6 +16,7 @@ clock: ?[:0]const u8 = null,
 console_dev: [:0]const u8 = "/dev/console",
 default_input: Input = .login,
 fg: u8 = 8,
+cmatrix_fg: u8 = 3,
 hide_borders: bool = false,
 hide_key_hints: bool = false,
 initial_info_text: ?[]const u8 = null,