Add upload and installation errors.

res/app/components/stf/upload/index.js

@@ -0,0 +1,4 @@
+module.exports = angular.module('stf.upload-service', [
+  require('gettext').name
+])
+  .filter('uploadError', require('./upload-error-filter'))

res/app/components/stf/upload/upload-error-filter.js

@@ -0,0 +1,10 @@
+module.exports = function uploadErrorFilter(gettext) {
+  return function (text) {
+    return {
+      'fail_invalid_app_file': gettext('Uploaded file is not valid'),
+      'fail_download': gettext('Failed to download file'),
+      'fail_invalid_url': gettext('Cannot access specified URL'),
+      'fail': gettext('Upload failed')
+    }[text] || gettext('Upload unknown error')
+  }
+}

res/app/components/stf/upload/upload-spec.js

@@ -0,0 +1,13 @@
+describe('upload', function() {
+
+  beforeEach(angular.mock.module(require('./').name))
+
+	it('should ...', inject(function($filter) {
+
+    var filter = $filter('upload')
+
+		expect(filter('input')).toEqual('output')
+
+	}))
+
+})