docs: creation of basic structure

initial adding of config (based on pmb/docs)

.ci/docs.sh

+#!/bin/sh -e
+# Description: create documentation with sphinx
+# Options: native
+# https://postmarketos.org/pmb-ci
+
+
+# Ensure sphinx_rtd_theme is installed
+if [ "$(id -u)" = 0 ]; then
+	set -x
+	apk -q add \
+		py3-myst-parser \
+		py3-sphinx_rtd_theme \
+		py3-sphinxcontrib-autoprogram 
+	exec su "${TESTUSER:-pmos}" -c "sh -e $0"
+fi
+
+# Require sphinx to be installed on the host system
+if [ -z "$(command -v sphinx-build)" ]; then
+	echo "ERROR: sphinx-build command not found, make sure it is in your PATH."
+	exit 1
+fi
+
+sphinx-build \
+	docs \
+	public \
+
+#	-E -a -v -T