Update Dockerfile: Use Poetry instead of Pip

Also:
Remove multi-stage (Need to be added in the future to minimize the image)

.dockerignore

@@ -109,6 +109,7 @@ venv/
 ENV/
 env.bak/
 venv.bak/
+.env.example
 
 # Spyder project settings
 .spyderproject
@@ -144,12 +145,10 @@ tests/
 # https://github.com/marketplace/renovate
 renovate.json
 
-# Other files not needed in the Docker image
+# Git files and directories
 .git/
-README.md
-pyproject.toml
-poetry.lock
-LICENSE
+.gitignore
+
+# Docker files
 docker-compose.yml
 Dockerfile
-.gitignore