Reorganize directories (#3462)

* 🚚 move files
* 🚚 rename doc folder to docs
* 🚚 rename test folder to tests

docs/mkdocs/Makefile

@@ -0,0 +1,36 @@
+# serve the site locally
+serve: prepare_files style_check
+	venv/bin/mkdocs serve
+
+serve_dirty: prepare_files style_check
+	venv/bin/mkdocs serve --dirtyreload
+
+build: prepare_files style_check
+	venv/bin/mkdocs build
+
+# create files that are not versioned inside the mkdocs folder (images, examples)
+prepare_files: clean
+	mkdir docs/examples
+	cp -r ../json.gif docs/images
+	cp -r ../examples/*.cpp ../examples/*.output docs/examples
+
+style_check:
+	@cd docs ; python3 ../scripts/check_structure.py
+
+# clean subfolders
+clean:
+	rm -fr docs/images/json.gif docs/examples
+
+# publish site to GitHub pages
+publish: prepare_files
+	venv/bin/mkdocs gh-deploy --clean --force
+
+# install a Python virtual environment
+install_venv: requirements.txt
+	python3 -mvenv venv
+	venv/bin/pip install wheel
+	venv/bin/pip install -r requirements.txt
+
+# uninstall the virtual environment
+uninstall_venv: clean
+	rm -fr venv