Fixed yarn dev --stripe ignoring HTTPS configured sites

- because the cwd of `.github/dev.js` is not `ghost/core`, it doesn't
  pick up config.local.json files, so any configuration you set in there
  isn't applied
- this meant that developers with HTTPS configured locally couldn't use
  `--stripe` because it wouldn't configure the Stripe listening URL
  correctly
- this adds an exports to the config lib to allow passing options in,
  which I then utilize to pass the directory that config resides in
- this should fix the aforementioned problem with HTTPS

.github/dev.js

@@ -4,7 +4,10 @@ const exec = util.promisify(require('child_process').exec);
 
 const concurrently = require('concurrently');
 
-const config = require('../ghost/core/core/shared/config');
+const config = require('../ghost/core/core/shared/config').withOptions({
+    customConfigPath: path.join(__dirname, '../ghost/core')
+});
+
 const liveReloadBaseUrl = config.getSubdir() || '/ghost/';
 const siteUrl = config.getSiteUrl();
 

ghost/core/core/shared/config/index.js

@@ -1,3 +1,4 @@
 const loader = require('./loader');
 
 module.exports = loader.loadNconf();
+module.exports.withOptions = (options) => loader.loadNconf(options);