Add a Dockerignore file (#72)

* Add required library libatomic1 to Dockerfile

* Add a dockerignore file

It used to take like 3 seconds to copy all the files into the Docker image because `.venv` was included.

That isn't needed because we `uv sync` within the container, so builds are slightly faster during development now.

Author: MMK21Hub

.dockerignore

@@ -0,0 +1,10 @@
+# Python-generated files
+__pycache__/
+*.py[oc]
+build/
+dist/
+wheels/
+*.egg-info
+
+# Virtual environments
+.venv