start-cloud.sh implicitly requires python, virtualenv and npm

[v-pan]

Prerequisites listed in README.md are docker and docker-compose. The start scripts, however, call global installations of python and npm. Either the prerequisites list should be updated, or the start scripts shouldn't depend on global installations.

Example issue when running start-cloud.sh

./start-cloud.sh: line 13: virtualenv: command not found
./start-cloud.sh: line 14: bin/activate: No such file or directory
./start-cloud.sh: line 15: pip3: command not found
./start-cloud.sh: line 16: cd: /home/therapod/repos/netsoc-dev-env/cloud/ui: No such file or directory
./start-cloud.sh: line 17: npm: command not found

which later leads into

api.netsoc.test    | ModuleNotFoundError: No module named 'v1'

...

cloud.netsoc.test  | npm ERR! enoent ENOENT: no such file or directory, open '/app/package.json'