[#355] add BaiduMap preview in new/edit event page
#355 Refactor move inline javacript to external js file
#355 Display baidu map on event show page
#355 add initializers file for baidu map, make it posoible for user to enable/disable baidu map throught config key
#355 add access key request link in initializer file
#355 Refactor code. move baidumap_ak from initializers to settings.yml; debounce updateMap function