Revert "Add no-use-before-define linter rule"

This reverts commit fdcc5d68a2.

Unfortunately, this requires us to move exports to the bottom.
This in turn causes circular dep issues and also access of
exports.GLOBAL_VAR in the global context

src/backupintegrity.js

@@ -1,5 +1,9 @@
 'use strict';
 
+exports = module.exports = {
+    check
+};
+
 const backups = require('./backups.js'),
     backupFormats = require('./backupformats.js'),
     backupSites = require('./backupsites.js'),
@@ -32,6 +36,3 @@ async function check(backupId, progressCallback) {
     };
 }
 
-exports = module.exports = {
-    check
-};