Fixing deployment errors

[uo289689]

Fixing tests and deployment configuration errors.

We had two main issues that where finally solved:

• @uo289689 found that we had not defined an environmental variable (REACT_APP_API_ENDPOINT) in the webapp container of the Dockerfile file. This led to various exceptions when executing the application.
• @uo288347 discovered that we had not eliminated the Docker containers in the Virtual Machine that were used for another deployment. This caused an anomalous behaviour of the application.