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 :)
I'd love to but `tracker.ACTIONS` aren't the only part of `tracker` module which is being used in `intMapUtils`. If I move it to config then I'll have to create a dependency of `intMapConfig` in `intMapUtils`. I don't think we want this :dolls: