Feature/430 add images to project

[macfleury-2000]

Description

A few sentences describing the overall goals of the pull request's commits.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist

• My code follows the style guidelines of this project
• I did not update API Controllers, if I did, I added/changed Postman tests
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I updated the changelog with an end-user readable description
• I assigned this pull request to the correct project board to update the sprint board

Steps to Test or Reproduce

1. Add a file (image)
2. Add a project with multiple files
3. Open project and note that the right files are added

Link to issue

Closes: #430

[JVerbruggen]

Looks good! Please look at the requested changes. Nice GitHub name btw xdd

[JVerbruggen]

Also take a look at why the unit & integration tests fail

[waltersajtos]

There was something weird going on with the File class types. All other changes look good, good work!

[TimSnoek123]

Prima.

[JVerbruggen]

LGTM!