[other] Reduce npm package size (wix#6759)

| After | Before |
|---|---|
| package size:  `1.1 MB` , unpacked size: `4.2 MB`   | package size:  `2.3 MB`, unpacked size: `5.4 MB`  |

```sh
npm pack # to test
```

- https://npmfs.com/package/react-native-navigation/7.3.0/

![image](https://user-images.githubusercontent.com/4661784/98730305-bf897f00-23a4-11eb-9d17-d343d85d3f19.png)

![image](https://user-images.githubusercontent.com/4661784/98730215-a1bc1a00-23a4-11eb-9bb4-4e3a5259c6ab.png)


```
$ find . -type f | egrep ".(test|spec).(js|jsx|ts|tsx|d.ts)"

./react-native-navigation-hooks/dist/index.test.d.ts
./react-native-navigation-hooks/dist/index.test.d.ts.map
./react-native-navigation-hooks/dist/index.test.js
./react-native-navigation-hooks/dist/index.test.js.map
./react-native-navigation/lib/dist/commands/Commands.test.d.ts
./react-native-navigation/lib/dist/commands/Commands.test.js
./react-native-navigation/lib/dist/commands/LayoutTreeCrawler.test.d.ts
./react-native-navigation/lib/dist/commands/LayoutTreeCrawler.test.js
./react-native-navigation/lib/dist/commands/LayoutTreeParser.test.d.ts
./react-native-navigation/lib/dist/commands/LayoutTreeParser.test.js
./react-native-navigation/lib/dist/commands/LayoutType.test.d.ts
./react-native-navigation/lib/dist/commands/LayoutType.test.js
./react-native-navigation/lib/dist/commands/OptionsProcessor.test.d.ts
./react-native-navigation/lib/dist/commands/OptionsProcessor.test.js
./react-native-navigation/lib/dist/components/ComponentRegistry.test.d.ts
./react-native-navigation/lib/dist/components/ComponentRegistry.test.js
./react-native-navigation/lib/dist/components/ComponentWrapper.test.d.ts
./react-native-navigation/lib/dist/components/ComponentWrapper.test.js
./react-native-navigation/lib/dist/components/Store.test.d.ts
./react-native-navigation/lib/dist/components/Store.test.js
./react-native-navigation/lib/dist/events/CommandsObserver.test.d.ts
./react-native-navigation/lib/dist/events/CommandsObserver.test.js
./react-native-navigation/lib/dist/events/ComponentEventsObserver.test.d.ts
./react-native-navigation/lib/dist/events/ComponentEventsObserver.test.js
./react-native-navigation/lib/dist/events/EventsRegistry.test.d.ts
./react-native-navigation/lib/dist/events/EventsRegistry.test.js
./react-native-navigation/lib/src/commands/Commands.test.ts
./react-native-navigation/lib/src/commands/LayoutTreeCrawler.test.ts
./react-native-navigation/lib/src/commands/LayoutTreeParser.test.ts
./react-native-navigation/lib/src/commands/LayoutType.test.ts
./react-native-navigation/lib/src/commands/OptionsProcessor.test.ts
./react-native-navigation/lib/src/components/ComponentRegistry.test.tsx
./react-native-navigation/lib/src/components/ComponentWrapper.test.tsx
./react-native-navigation/lib/src/components/Store.test.ts
./react-native-navigation/lib/src/events/CommandsObserver.test.ts
./react-native-navigation/lib/src/events/ComponentEventsObserver.test.tsx
./react-native-navigation/lib/src/events/EventsRegistry.test.tsx
```


Co-authored-by: Guy Carmeli <[email protected]>

Author: retyui

.npmignore

@@ -229,3 +229,35 @@ buck-out/
 \.buckd/
 lib/android/app/libs
 lib/android/keystores/debug.keystore
+
+# Tests
+**/*.test.js
+**/*.test.jsx
+**/*.test.ts
+**/*.test.d.ts
+**/*.test.tsx
+
+# TS configs
+tsconfig.build.json
+tsconfig.json
+tsconfig-strict.json
+tslint.json
+
+# Eslint
+.eslintignore
+.eslintrc.js
+
+# Docs
+CONTRIBUTING.md
+
+# Editor
+.vscode
+jsconfig.json
+
+# Other
+babel.config.js
+.watchmanconfig
+.logo.png
+.grenrc.js
+.clang-format
+.prettierrc