Add more important dates to bounty infos

### User Story
As a hackathon bounty participant, I want to see all important dates about the bounty so that i know when judging will be ended, the winners will be announced and the payouts will be made.

### Why Is this Needed
For now a hackathon bounty has a start and an end date. It is also important to know when which steps are planned e.g. judging, winners announced, payouts. I participated to a lot of bounties, where you have to wait several weeks for payouts (e.g. the last SkyDB hackathon). For more transparency and user-friendliness.

*Summary*:
### Description
*Type*: Feature

### Current Behavior
Bounty infos has just two dates:
* Bounty start (date)
* Bounty submission (date)

### Expected Behavior
Bounty infos has more important dates:
* Bounty start (date)
* Bounty submission (date)
* Judging (date)
* Winners (date)
* Payouts (date)

### Definition of Done
Points defined at _Expected Behavior_ are implemented.