set up CI workflow to deploy docs

.github/actions/publish-docs.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+
+HOST="$1"
+HOST_PATH="$2"
+SSH_PRIVATE_KEY="$3"
+SSH_KNOWN_HOST="$4"
+SSH_PRIVATE_KEY_PATH="$HOME/.ssh-ci/${GITHUB_REPOSITORY:-publish-docs}"
+
+if [ "$#" -ne 4 ]; then
+  echo -e "not enough arguments USAGE:\n\n$0 \$HOST \$HOST_PATH \$SSH_PRIVATE_KEY \$SSH_KNOWN_HOSTS\n\n" >&2
+  exit 1
+fi
+
+install -m 600 -D /dev/null "$SSH_PRIVATE_KEY_PATH"
+echo "$SSH_PRIVATE_KEY" > "$SSH_PRIVATE_KEY_PATH"
+echo "$SSH_KNOWN_HOST" > ~/.ssh/known_hosts
+rsync --delete -avze "ssh -i $SSH_PRIVATE_KEY_PATH" docs/build/site/ "$HOST:$HOST_PATH"
+rm -f "$SSH_PRIVATE_KEY_PATH"