implement universal-loader w/caching

[fulls1z3]

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[ ] bug report => check the README and search github for a similar issue or PR before submitting
[ ] support request => check the README and search github for a similar issue or PR before submitting
[X] feature request

Current behavior
@nglibs/i18n-router does not have a loader for Angular Universal, using the fs to retrieve data.

Expected/desired behavior
The universal-loader must be implemented - retrieving the data using the fs on the server platform, and then caching the result when it will be requested again on the client platform.

Related issue: fulls1z3/universal#5

Minimal reproduction of the problem with instructions

What is the motivation / use case for changing the behavior?

Please tell us about your environment:

• Angular version: 2.0.X

• Browser: [all | Chrome XX | Firefox XX | IE XX | Safari XX | Mobile Chrome XX | Android X.X Web Browser | iOS XX Safari | iOS XX UIWebView | iOS XX WKWebView ]

• Language: [all | TypeScript X.X | ES6/7 | ES5]

• Node (for AoT issues): node --version =