fix create_default_project.sh

[mtxslv]

From line 24 on in create_default_project.sh, we see the following sequence of commands:

poetry install
poetry add <some-pkg>

something that is throwing errors. Actually, the order must be the opposite:

poetry add <some-pkg>
poetry install

This is because first we must add anything in order to start the virtual environment. If the venv is not initialized, it makes no sense to install the project into it.