add ability to acknowledge help request

:bulb: general idea, following #3 

1. as a **supporter** I should be able to acknowledge support request.
2. as a **support requester** I should receive emails when support is acknowledged so I know that someone is helping me (in one way or another)
3. as a **person with too much time and fast response** I should be able to acknowledge other people's requests if such request hasn't been acknowledged yet

:warning: still work in progress