Dynamic Routing: Added migration for routes.yaml file (#9692)

refs #9601

- the home.hbs behaviour for the index collection (`/`) is hardcoded in Ghost
- we would like to migrate all existing routes.yaml files
- we only replace the file if the contents of the routes.yaml file equals the old routes.yaml format (with home.hbs as template)
- updated README of settings folder
- if we don't remove the home.hbs template from the default routes.yaml file, home.hbs will be rendered for any page of the index collection
  - the backwards compatible behaviour was different
  - only render home.hbs for page 1
- remember: the default routes.yaml file reflects how Ghost was working without dynamic routing

ghost/security/lib/tokens.js

@@ -1,6 +1,20 @@
 const crypto = require('crypto');
 
-module.exports.generateHash = function generateHash(options) {
+module.exports.generateFromContent = function generateFromContent(options) {
+    options = options || {};
+
+    const hash = crypto.createHash('sha256'),
+        content = options.content;
+
+    let text = '';
+
+    hash.update(content);
+
+    text += [content, hash.digest('base64')].join('|');
+    return new Buffer(text).toString('base64');
+};
+
+module.exports.generateFromEmail = function generateFromEmail(options) {
     options = options || {};
 
     const hash = crypto.createHash('sha256'),