MWEB-850

* added unit tests for ContributionMenuController,
* added new item in the menu if maps are enabled,
* created new JS file which is loaded on every page view (`WikiaInteractiveMapsCreateMap.js`),
* extracted some common logic from `WikiaInteractiveMaps.js` to utils,
* created new module `intMapConfig`,
* added tracking for different create map entry points.

@macbre, do you mind checking the unit tests, please? We talked about them yesterday and I'd like you to take another look at it :)
there are some config values that could be moved to config module