Xamarin forms cognitive service

[susairajs]

Description of Change

Pull Request Checklist

• [✓ ] Rebased on top of master at time of the pull request.
• [ ✓ ] Changes adhere to coding standard in the sample.
• [ ✓ ] Consolidated NuGet packages across all projects in the sample (when changing existing package versions).
• [✓ ] Tested changes on the appropriate platforms (all platforms if changing the library code).

[conceptdev]

Hi @susairajs, thanks for taking the time to build a sample.

Please review the submission guidelines for this repo. Generally we do not accept unsolicited submissions, rather we prefer authors create an issue to propose their idea, which we can then discuss and agree on the goals and implementation, before too much work is done.

Since you've already done the work, we will review and let you know.