Updated AdsInsights spec + new AdsHistogramStats spec

[Just1B]

Checklist

• [X] I've read the Contributing Guidelines and the Code of Conduct
• [X] I've completed the Contributor License Agreement

Pull Request Details

• Updated AdsInsights spec based on Meta Documentation :https://developers.facebook.com/docs/marketing-api/reference/ad-account/insights/

• New AdsHistogramStats spec based on Graph Api Responses Observation ( no documentation available in Meta )