Update AGPL licenses in config and graphics files

src/config.rs

@@ -1,3 +1,6 @@
+// Copyright (c) 2022 Marceline Cramer
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
 use hex_color::HexColor;
 use serde::{Deserialize, Serialize};
 use std::path::PathBuf;

src/graphics.rs

@@ -1,3 +1,6 @@
+// Copyright (c) 2022 Marceline Cramer
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
 use std::collections::VecDeque;
 use std::time::Duration;