standardize loading of server configuration

lib/load-config.js

@@ -0,0 +1,12 @@
+var config;
+try {
+    config = require("../config/config");
+    if (config.adminEmail === 'i.did.not.read.my.config@cryptpad.fr') {
+        console.log("You can configure the administrator email (adminEmail) in your config/config.js file");
+    }
+} catch (e) {
+    console.log("You can customize the configuration by copying config/config.example.js to config/config.js");
+    config = require("../config/config.example");
+}
+module.exports = config;
+