feat: Update BountyStore to Support Multiple Featured Bounties

[Shoaibdev7]

Describe your changes

Issue ticket number and link: https://community.sphinx.chat/p/cs7n8c2tu2rivj8gup0g/bounties/3128/2

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist before requesting a review

• I have performed a self-review of my code
• I have tested on Chrome and Firefox
• I have tested on a mobile device
• I have provided a screenshot or recording of changes in my PR if there were updates to the frontend

[Shoaibdev7]

Hi @humansinstitute Please review this PR.