Add a bookmark button on bounty pages

### **Add a bookmark button on bounty pages**

This is a feature request on bounty pages.

**PROBLEM**: Presently, there’s the issue of searching and locating a bounty on the bounty page every time you want to refer to it for something (e.g. to get more info, check stats/submissions, new updates from funder, etc). This sometimes involve scrolling/ filtering through a long list of bounties on the explorer page (both hackathon and issues).

**SOLUTION**: It'd be really nice if there was a way to save or bookmark bounties, and see all your bookmarked bounties so you can easily access them later (maybe in the dashboard).

**SUGGESTIONS**:
- a good place to place the button might be next to the "share" button. This would make it easily visible.


- it’ll also be a good idea to see bounties that have been previously bookmarked when scrolling through the explorer page

It’ll be really easy for contributors to refer to and navigate in-between bounties, if you can consider implementing this feature.