[READY] extract StartNewDiscussion service

:white_check_mark: :  **CR** 

:white_check_mark: : **QA** 

>  pull down locally, check app loads

> *test core functionality of feature:*
>  start a new discussion  :ok: 

> *interact with everything in proximity of the core feature (e.g.):*
> posting comments  :ok: 
> edit discussion title  :ok: 
> start new discussion  :ok: 

> logged out functionality - N/A 
> public/ private functionality - N/A

> test in IE 8 Not necessary
> test in production environment - NA

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:white_check_mark: : **CO signoff** 
:ok: : **DO signoff** - nothing changed in interface

:question: : **PO signoff**

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useful symbols :white_check_mark: :ok: :x: :question: