Moved jest config from package.json to external file

jest.config.js

@@ -0,0 +1,33 @@
+module.exports = {
+  coverageDirectory: '<rootDir>/coverage',
+  collectCoverageFrom: [
+    'src/**/*.{js,jsx,mjs}',
+    '!src/registerServiceWorker.js',
+    '!src/index.js',
+  ],
+  setupFiles: [
+    '<rootDir>/config/polyfills.js',
+    '<rootDir>/config/setupEnzyme.js',
+  ],
+  testMatch: [ '<rootDir>/test/**/*.test.{js,jsx,mjs}' ],
+  testEnvironment: 'node',
+  testURL: 'http://localhost',
+  transform: {
+    '^.+\\.(js|jsx|mjs)$': '<rootDir>/node_modules/babel-jest',
+    '^.+\\.css$': '<rootDir>/config/jest/cssTransform.js',
+    '^(?!.*\\.(js|jsx|mjs|css|json)$)': '<rootDir>/config/jest/fileTransform.js',
+  },
+  transformIgnorePatterns: [ '[/\\\\]node_modules[/\\\\].+\\.(js|jsx|mjs)$' ],
+  moduleNameMapper: {
+    '^react-native$': 'react-native-web',
+  },
+  moduleFileExtensions: [
+    'web.js',
+    'js',
+    'json',
+    'web.jsx',
+    'jsx',
+    'node',
+    'mjs',
+  ],
+};