Allow customizing some of the server options

This passes in a few whitelisted keys from config.yml to override
defaults from the default `.screepsrc` file.

config.yml

@@ -1,6 +1,15 @@
 mods:
   - screepsmod-auth
-  - screepsmod-admin-utils
   - screepsmod-mongo
 bots:
   simplebot: screepsbot-zeswarm
+
+serverConfig:
+  # The number of parallel runner threads in which player scripts are executed.
+  # Don't set this option greater than the number of your physical CPU cores.
+  runner_threads: 4
+  # The number of room processor worker processes to launch.
+  # Don't set this option greater than the number of your physical CPU cores.
+  processors_cnt: 2
+  # If set, forward console messages to terminal
+  log_console: false

screeps-start.js

@@ -128,11 +128,20 @@ const start = async () => {
   writeModsConfiguration();
 
   const screeps = require("@screeps/launcher");
+  const options = {
+    steam_api_key: process.env.STEAM_KEY || config.steamKey,
+    storage_disable: false,
+  };
+
+  const keys = ['runner_threads', 'processors_cnt', 'log_console'];
+  for (const key of keys) {
+    if (options[key]) {
+      options[key] = config.serverConfig[key];
+    }
+  }
+
   await screeps.start(
-    {
-      steam_api_key: process.env.STEAM_KEY || config.steamKey,
-      storage_disable: false,
-    },
+    options,
     process.stdout,
   );
 };