Migration to styled-components

Here's a list based off @andrewda's list for adding unit tests to the app (https://github.com/gitpoint/git-point/issues/518), feel free to add/remove components if you think it's necessary.

**For newcomers:**
1. Choose the component you want to style
1. Comment here which component you'd like to work on
1. We'll update this list with your name
1. Make sure to include "before" and "after" screenshots in your submitted PR

# Loaders
- [x] LoadingListItem (@machour - #790)
- [x] LoadingMembersList (unclaimed)
- [x] LoadingRepositoryListItem (unclaimed)
- [x] LoadingRepositoryProfile (unclaimed)
- [x] LoadingUserListItem (@machour - #791)
- [x] LoadingModal (@machour - #792)

# Components
- [ ] IssueListItem (@josenaranjo - #578)
- [ ] RepositoryProfile (@shmesa22 - PR Pending)

# Screens

## issue
- [ ] EditIssue (unclaimed)
- [ ] IssueSettings (unclaimed)
- [x] NewIssue (unclaimed)
- [ ] PullMerge (unclaimed)

## repository
- [ ] IssueList (unclaimed)
- [ ] PullDiff (unclaimed)
- [ ] PullList (unclaimed)
- [ ] ReadMe (unclaimed)
- [ ] RepositoryCodeList (unclaimed)
- [ ] RepositoryFile (unclaimed)
- [x] Repository (@machour - #788)

Done:
- [x] Auth (@ZahraTee - #702)
- [x] Login (@machour - #787)
- [x] Notifications (@ZahraTee - #684)
- [x] Organization (@ZahraTee - #682)
- [x] Search (@Arjun-sna - #710)
- [x] User (@ZahraTee - #683)
- [x] Badge (@jpls93 – #535)
- [x] LoadingContainer (@machour - #782)
- [x] CodeLine (@josenaranjo – #561)
- [x] CommentInput (@shmesa22 – #596)
- [x] CommentListItem (@chinesedfan - #723)
- [x] DiffBlocks (@machour – #692)
- [x] EntityInfo (@MrLoh - #558)
- [x] ImageZoom (@MrLoh - #559)
- [x] InlineLabel (@binkpitch – #544)
- [x] IssueDescription (@josenaranjo - #563)
- [x] IssueEventListItem (@josenaranjo - #564)
- [x] LabelButton (@chinesedfan - #727)
- [x] LabelListItem (@pdong – #509)
- [x] Members (@shmesa22 - #606)
- [x] MentionArea (@binkpitch – #553)
- [x] NotificationIcon (@pdong – #510)
- [x] NotificationListItem (@LeoCp - #610)
- [x] ParallaxScroll (@shmesa22 - #607)
- [x] RepositoryListItem (@apoeco - #605)
- [x] RepositorySectionTitle (Useless component, see #730)
- [x] SectionList (@jamesg1 - #608)
- [x] StateBadge (@rkpasia - #715)
- [x] ViewContainer (@pdong – #508)
- [x] UserListItem (@shmesa22 - #601)
- [x] UserProfile (@chinesedfan – #724)
- [x] SearchBarAndroid (can't be migrated)