stop connection pooling

oof, got "too many connections" from mysql, this is probably gonna be a scaling issue in time… for now, stop requesting a pool of 5, even on dev lolol, and just go with a single connection per instance

src/server/db.js

@@ -7,8 +7,7 @@ async function connectToDb() {
     return globalDb;
   }
 
-  globalDb = await mysql.createPool({
-    connectionLimit: 5,
+  globalDb = await mysql.createConnection({
     host: "impress.openneo.net",
     user: process.env["IMPRESS_MYSQL_USER"],
     password: process.env["IMPRESS_MYSQL_PASSWORD"],