Refactor project and platform services

We need this refactoring in order to reuse code for `iOSProjectService`
You can use an array as a second argument here: https://github.com/arturadib/shelljs#cpoptions--source_array-dest.
Ex: 
```js
var paths = "assets gen libs res".split(' ').map(p => path.join(frameworkDir, path));
```