Making the navbar sticky for a better accessibility throughout the page

[Bhavil-Ahuja]

Expected Behavior

The navbar should exhibit a sticky behavior, i.e., as we roll down the page, the navbar should always be visible to us at the top of the page. This will make the navbar items easily accessible for the user and he/she would't need to scroll to the top.

Current Behavior

Currently, the navbar is present only at the top of the page followed by the rest of the page.

Please assign me this issue under GSSOC'23.

[Arnabdaz]

already being worked on #92