Update all dependencies to the lastest possible version

[grosspersky]

User Story

As a:

site maintainer

I want:

my application to have all the latest updates

so that:

i have a secure and up to date application

Acceptance criteria:

• [ ] Frontend uses Angular 7
• [ ] Other frontend dependencies (e.g. for testing) are up to date
• [x] All API Dependencies are up to date (dependabot)

Additional info:

Angular update instructions: https://update.angular.io/

This is blocked at the moment since some frontend dependencies need a new version to be compatible with Angular 7.