feat: implement WebADIS authentication and add medianumber retrieval functionality

src/backend/migrations/V002__create_table_webadis_login.sql

@@ -0,0 +1,10 @@
+BEGIN TRANSACTION;
+
+CREATE TABLE IF NOT EXISTS webadis_login (
+    id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
+    username TEXT NOT NULL,
+    password TEXT NOT NULL
+  );
+
+COMMIT;
+