Mob 1778 (Batch methods for POI categories)

@aquilax @nandy-andy @rogatty @RafLeszczynski -> This will make us do all POST requests as arrays of objects, PUT and DELETE will be available for both wildcard (with id in url) and in general entry point.
consider taking callbacks out 
so you have less of a callback hell

there is proposed PR that mentions that
https://github.com/Wikia/guidelines/pull/16/files