Implement pagination improvements(# 9102)

[akshay-gupta7]

In response to issue #9102 :

• Inline JavaScript in https://github.com/wagtail/wagtail/blob/main/docs/_templates/search.html has been moved to separate external JS file
• onclick events has been replaced with addEventListener events
• Now one button per page is displayed, Page 2 of 7, along with a previous and a Next button

[squash-labs]

Manage this branch in Squash

Test this branch here: https://akshay-gupta7pagination-update-qtxvy.squash.io

[akshay-gupta7]

Adding another PR with resolved lint errors

[zerolab]

@akshay-gupta7 you can push your changes to the existing branch akshay-gupta7:pagination-update and this PR should pick up the changes without the need to open a new PR

[akshay-gupta7]

@zerolab , thank you for the suggestion.
However, I have already opened a fresh PR. Let me if I should close the new one and reopen this PR.

[zerolab]

No need, it is done now. but do keep that in mind for the future.

[akshay-gupta7]

Definitely, shall keep this in mind @zerolab.