Fix search functionality

[NitanJana]

Summary

This PR should close #5 by fixing the searchbar.

Functionality implemented

• [x] indexes the whole site at build time.
• [x] searchbar resets at route change.
• [x] show only at /blog and /learning.
• [x] fix dev mode.

[NitanJana]

@yaralahruthik sorry for the conflict, didn't see you merged my previous commit.