ci: add unit test workflow and package setup for ldapsm

- Add GitHub Actions workflow to run make test
- Introduce pyproject.toml with python-ldap dependency and CLI entrypoint
- Add Makefile with install/test/clean targets
- Move tests to src-based package layout and fix imports
- Remove legacy requirements.yml

https://chatgpt.com/share/695d2615-d664-800f-b821-5705c631bfe8

Makefile

@@ -0,0 +1,23 @@
+.PHONY: help install test lint clean
+
+PYTHON          ?= python3
+PROJECT_NAME    := ldapsm
+SRC_DIR         := src
+TEST_DIR        := tests
+
+help:
+	@echo "Available targets:"
+	@echo "  install   Install project in editable mode"
+	@echo "  test      Run unit tests"
+	@echo "  clean     Remove Python cache files"
+
+install:
+	$(PYTHON) -m pip install --upgrade pip
+	$(PYTHON) -m pip install -e .
+
+test:
+	$(PYTHON) -m unittest discover -s $(TEST_DIR) -p "test_*.py"
+
+clean:
+	find . -type d -name "__pycache__" -exec rm -rf {} +
+	find . -type f -name "*.pyc" -delete