Refactor GitHub workflows

This mostly simplifies our GitHub actions, but also fixes recent
breaking in the release workflows, unifies the tagged and nightly
release workflows, and moves to using `gh release` to manage releases.

Signed-off-by: Jonathon Anderson <janderson@ciq.com>

.github/workflows/userdocs.yml

@@ -0,0 +1,73 @@
+---
+name: userdocs
+
+on:
+  workflow_dispatch: {}
+  push:
+    branches:
+      - main
+      - 'v4.*.x'
+    paths:
+      - 'userdocs/**'
+  pull_request:
+    branches:
+      - main
+      - 'v4.*.x'
+
+jobs:
+  publish:
+    if: ${{ github.repository_owner == 'warewulf' }}
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: recursive
+      - uses: actions/setup-python@v5
+
+      - name: prepare
+        run: |
+          sudo apt update
+          sudo apt-get install -f -y texlive-latex-extra latexmk graphviz pandoc
+          pip install --user --upgrade --upgrade-strategy eager sphinx sphinx-rtd-theme restructuredtext_lint pygments sphinx_reredirects
+
+      - name: make generated docs
+        run: |
+          make docs
+          mkdir -p userdocs/reference/man5
+          for f in docs/man/man5/*.5
+          do
+            title="$(basename "${f%.5}")"'(5)'
+            output="userdocs/reference/man5/$(basename "${f%.5}.rst")"
+            line=$(printf '=%.0s' $(seq ${#title}))
+            printf "%s\n%s\n%s\n\n" "$line" "$title" "$line" > "$output"
+            pandoc -f man -t rst "$f" >> "$output"
+          done
+
+      - name: build userdocs
+        run: |
+          make -C userdocs html
+
+      - name: publish docs to github.com/warewulf/warewulf.org
+        if: github.event_name != 'pull_request'
+        env:
+          SSH_AUTH_SOCK: /tmp/ssh_agent.sock
+        run: |
+          mkdir -p ~/.ssh
+          ssh-keyscan github.com >> ~/.ssh/known_hosts
+          echo "${{ secrets.GH_DEPLOY_KEY }}" > ~/.ssh/id_rsa
+          chmod 600 ~/.ssh/id_rsa
+          cat <<EOT >> ~/.ssh/config
+          Host github.com
+          HostName github.com
+          IdentityFile ~/.ssh/id_rsa
+          EOT
+          git config --global user.email "actions@github.com"
+          git config --global user.name "gh-actions"
+          git clone git@github.com:warewulf/warewulf.org.git ~/warewulf-web
+          mkdir -p ~/warewulf-web/static/docs
+          rm -rf ~/warewulf-web/static/docs/${GITHUB_REF##*/}
+          cp -r userdocs/_build/html ~/warewulf-web/static/docs/${GITHUB_REF##*/}
+          cd ~/warewulf-web
+          git add static/docs/${GITHUB_REF##*/}
+          git commit -m "Update ${GITHUB_REF##*/} docs"
+          git push