Connecting image gallery with backend

[andrezz-b]

Description

Image gallery UI is now connected to the backend. Other changes:

• Fixed #101
• AWS keys are handled automatically by AWS so they don't need to be passed to the docker
• Moved some methods from the frontend's UsersService into a new MatchesService

  Configuration

  @SaraKalcic @kovacevicdominik @petra5555 @marinivosevic @smaln

  Docker

  There were some changes in configuration for AWS so you should change your secrets.properties

  Old secrests.properties

  # ... Other configurations ...
  aws.accessKey=access
  aws.secretKey=secret
  aws.region=europe
  # ... Other configurations ...

  New secrests.properties

  # ... Other configurations ...
  spring.cloud.aws.credentials.access-key=<ACCESS_KEY>
  spring.cloud.aws.credentials.secret-key=<SECRET_KEY>
  # ... Other configurations ...

  Without Docker

  Run the app using AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables. Or choose an alternative method like number 4 here.

[andrezz-b]

@SaraKalcic @kovacevicdominik I have deployed this without the last 2 commits (the deployed version doesn't work for the usres with old base64 images and the area for uploading images might be stretched out if it's a large image). So can you check everything else by:

1. Creating a new user and setting a profile picture
2. Changing the profile picture
3. Adding a new photo in the gallery
4. Removing the photo from the gallery

[SaraKalcic]

Everything looks and works great, frontend and backend wise.