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.
This is a case which needs to have dbCon to redirect all the affected POI to generic category by calling handleUsedCategories or rollback the transaction if it is another case. handleUsedCategories calls errorHandler if needed.