Moved i18n to correct location in boot process

- Note: added a forced error to show that this was previously happening at the wrong time
- i18n is required by ghost-server to log server start messages, and so gets initialised as part of the ghost-server load
- moving this into the right place means we can see how long it takes in the debug logs
- previously the debug log lines for i18n showed 0/1ms, which is not correct as this contains a sync file load operation!
- we should consider if we want to have i18n be a requirement for ghost server, or if we want static messages

core/boot.js

@@ -55,13 +55,6 @@ async function initDatabase({config, logging}) {
  */
 async function initCore({ghostServer}) {
     debug('Begin: initCore');
-
-    // Initialize Ghost core internationalization - this is basically used to colocate all of our error message strings
-    debug('Begin: i18n');
-    const i18n = require('./shared/i18n');
-    i18n.init();
-    debug('End: i18n');
-
     // Models are the heart of Ghost - this is a syncronous operation
     debug('Begin: models');
     const models = require('./server/models');
@@ -264,6 +257,12 @@ async function bootGhost() {
         require('./shared/sentry');
         debug('End: Load sentry');
 
+        // I18n is basically used to colocate all of our error message strings & required to log server start messages
+        debug('Begin: i18n');
+        const i18n = require('./shared/i18n');
+        i18n.init();
+        debug('End: i18n');
+
         debug('Begin: Load urlUtils');
         const urlUtils = require('./shared/url-utils');
         debug('End: Load urlUtils');

core/shared/i18n/i18n.js

@@ -143,7 +143,7 @@ class I18n {
 
         // If not in memory, load translations for core
         if (isNil(this._strings)) {
-            this.init();
+            throw new errors.IncorrectUsageError({message: 'i18n was used before it was initialised'});
         }
 
         candidateString = this._getCandidateString(msgPath);