Feature Request — Use virtual env for the yacs_api docker image

**Job**
Currently, the docker image for `yacs_api` just copies python files into `/usr/src` instead of using a virtual environment.
This can cause issues with people not running docker as root as `/usr/src` is owned by root in the docker image.

**Describe a possible solution**
Use a virtual env in the build steps for `yacs_api`
