UI: Develop Sign In page

## Description
As a maintainer,
I need to see BIT Sign Up page gets redesigned,
so that I can make sure they meet AnitaB guidelines.

## Mocks
Approved design idea for Sign In page (Designer Gloria Osoro)

## Acceptance Criteria
### Update [Required]
- [ ] Implement the design above in the section it is intended in the design above.

### Enhancement to Update [Optional]
NA

## Definition of Done
- [ ] All of the required items are completed.
- [ ] Approval by 1 mentor.

## Estimation
1 day