[Angular + NgRx + SCSS] Create main page layout (top repositories + gists)

# Create main page layout

## Background

As a user, my main page view should show me my gists and top repositories.

## Acceptance


 - [ ] 2 column layout
 - [ ] Left side
    - [ ] gists panel
 - [ ] Right side
    - [ ] Top repositories title
    - [ ] card for each of the users’ top repos
    - [ ] view all repositories button that navigates to user profile page

## Notes