Resolve "pip install build"

Closes #17 (closed)

The corresponding merge request on the server side (ewoksserver!9 (merged)) makes the server serve ewoksweb.

Inspired by this with the addition of python namespace packages.

Install REST server only:

pip install ewoksserver

Install REST server with frontend:

pip install ewoksserver[frontend]

or alternatively

pip install ewoksserver
pip install ewoksweb

The deployment pipeline (runs fully on merge to main branch) looks like this: https://gitlab.esrf.fr/workflow/ewoks/ewoksweb/-/pipelines/72623 The last job (assets) contains the assets that can be deployed to pypi when needed.