[infra] move the docs build machinery into ./docs

doc/Makefile

@@ -0,0 +1,16 @@
+all:
+	@echo "This makefile is for building documentation"
+	@echo "in the virtual environment via '. ./venv.bash'"
+	@echo ""
+	@echo "Valid targets:"
+	@echo ""
+	@echo "    docs: build the sphinx documentation in ./html"
+	@echo "    clean: clean out the html directory"
+
+docs:
+	sphinx-build -v -b html . html
+
+clean:
+	rm -rf html
+
+.PHONY: docs clean

docenv.bash → doc/venv.bash

@@ -89,10 +89,10 @@ fi
 
 # Get all dependencies for doc generation
 # pip install -e .[docs]
-pip install -r doc/requirements.txt
+pip install -r requirements.txt
 
 # NB: this automagically nabs install_requires
-python setup.py develop
+python ../setup.py develop
 
 echo ""
 echo "Leave the virtual environment with 'deactivate'"