Add public keys and blocked servers routes

Introduces two new routes: one for serving public keys from the certificates manager at /minecraftservices/publickeys, and another for listing blocked servers from the sessions service at /sessionsserver/blockedservers. These endpoints provide necessary data for authentication and server validation processes.

routes/sessionsserver/blockedservers.js

@@ -0,0 +1,18 @@
+const express = require("express")
+const router = express.Router()
+const sessionsService = require("../../services/sessionsService")
+const { DefaultError } = require("../../errors/errors")
+
+router.get("", async (req, res) => {
+    const serviceResult = await sessionsService.getBlockedServers()
+    if (serviceResult instanceof DefaultError) {
+        return res.status(200).send("")
+    }
+    const finalList = []
+    for (const server of serviceResult.blockedServers) {
+        finalList.push(server.sha1)
+    }
+    return res.status(200).send(finalList.join("\r\n"))
+})
+
+module.exports = router