Add blog upvote feature

[Prajwal-kp-18]

Description:
Implement a feature that allows users to upvote blog posts.

Tasks:

• Add an upvote button for each blog post.
• Update the upvote count when a user clicks the button.
• Prevent multiple upvotes from the same user.

Expected Outcome:
Users can upvote blog posts, and the upvote count updates correctly.