MOB-2272 - translations in embedded maps

* changed the way embedded map source is generated,
* added new method `utils.addTrailingSlash()`,
* added unit tests.
Can you change parameters order so they are the same as in `setupMapRender(app, apiEntryPointUrlV1, apiConfigUrl)`? It's not a big issue, just would look better and shouldn't be difficult. I think this is the only place where `middleware()` is called.