#169 LoginPage, RegisterPage, Home saves/uses user_id, screenshot_key to/from local storage

[laila1222]

Changes in this PR:

• User_id and Screenshot_id are saved into local storage instead of context files
• Homepage:
  • when user logs out, local storage user_id is set to 1, and screenshot_key is set to ""
  • screensot_key is saved into local storage
• LoginPage:
  • Added LoginPage css file from storybook, enabled images
  • New request for getting user_id by email
  • User_id is saved to local storage
• RegisterPage:
  • New request for getting user_id by email
• Router and controllers:
  • Created new route for getting user_id by email
• Database:
  • Created new column for email
• Added documentation in swagger

How to test:

• Open Google Devtools, go to Application, login or register and check if the user_id in local storage changes.
• Log out (you can do that on homepage if you are already signed in), and chechk if user_id and screenshot_key (if applicable) turns to 1 . (screenshot_key should turn to "").
• Create a screenshot, and see if screenshot_key appears in local storage.
• Try signing in/registering by social media logins. I noticed that when I use my email that has permission to the firebase project, there's no new user created in database.