feat: add gravatar profile picture integration

frontend/src/lib/utils/crypto-util.ts

@@ -0,0 +1,7 @@
+export async function createSHA256hash(input: string) {
+	const msgUint8 = new TextEncoder().encode(input); // encode as (utf-8) Uint8Array
+	const hashBuffer = await crypto.subtle.digest('SHA-256', msgUint8); // hash the message
+	const hashArray = Array.from(new Uint8Array(hashBuffer)); // convert buffer to byte array
+	const hashHex = hashArray.map((b) => b.toString(16).padStart(2, '0')).join(''); // convert bytes to hex string
+	return hashHex;
+}