Added search bar in Django Admin Users page for emails and username

@ mention of reviewers`

@ihsaan-ullah @Didayolo`

Description

Added a search bar in the Django admin interface for the Users page. We can now look up Users bases on their username and emails. We can also easily add a search bar in other pages for different fields in later PRs

I tested it locally and everything worked fine.

Checklist

• Code review by me
• Hand tested by me
• I'm proud of my work
• Code review by reviewer
• Hand tested by reviewer
• CircleCi tests are passing
• Ready to merge