Create new Backend Group - Model for sendgrid / create-contact

Backend API on Swagger: [https://staging.fightpandemics.work/api/documentation/index.html#/default](https://staging.fightpandemics.work/api/documentation/index.html#/default)

Create new Group Backend (please review MVVM architecture - if you have any questions, please reach out to Scott (@Power186)

Start with the Swagger API documentation linked in the issue and review the existing MVVM architecture in the iOS project. Identify how a new backend group model should represent the SendGrid create-contact endpoint. Done means the model and group fit the project’s MVVM structure and support that endpoint.

Written by the indexing model from the issue text.