docs: add Elastic docs CI workflows

.github/workflows/docs-build.yml

@@ -0,0 +1,20 @@
+---
+name: docs-build
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened]
+  push:
+    branches:
+      - main
+  merge_group: ~
+
+permissions:
+  contents: read
+  pull-requests: read
+
+jobs:
+  build:
+    uses: elastic/docs-actions/.github/workflows/docs-build.yml@v1
+    with:
+      enable-vale-linting: true

.github/workflows/docs-deploy.yml

@@ -0,0 +1,20 @@
+---
+name: docs-deploy
+
+on:
+  workflow_run:
+    workflows: [docs-build]
+    types: [completed]
+
+permissions:
+  contents: read
+  deployments: write
+  id-token: write
+  pull-requests: write
+  actions: read
+
+jobs:
+  deploy:
+    uses: elastic/docs-actions/.github/workflows/docs-deploy.yml@v1
+    with:
+      enable-vale-linting: true

.github/workflows/docs-preview-cleanup.yml

@@ -0,0 +1,15 @@
+---
+name: docs-preview-cleanup
+
+on:
+  pull_request_target:
+    types:
+      - closed
+
+jobs:
+  cleanup:
+    uses: elastic/docs-actions/.github/workflows/docs-preview-cleanup.yml@v1
+    permissions:
+      contents: none
+      id-token: write
+      deployments: write

.gitignore

@@ -17,3 +17,6 @@ megalinter-reports/
 
 # Generated functional test scripts
 test/functional/es/
+
+# docs-builder local build output
+docs/.artifacts