Refactor login form to use react hooks

[damianstasik]

Another try at refactoring the remaining components to use hooks as part of the #58.

• Moved social sign-in component inside the render function, no need for the expensive recreation during re-renders
• Added state hooks for state properties that were uninitialized in the class version

[razvanilin]

Thanks for the PR!

It does not work as intended, though. Same issues as #68 #68 (review)

Please always test the changes on a vital component such as the Login form

[razvanilin]

Already refactored, closing