reconfigure branch for local builds and as scheduler for docs workflows

- set up placeholder and trigger for Deploy Docs workflow in docs-build branch
- set up placeholder and trigger for Rebuild Search Index workflow in docs-build branch
- remove obsolete Deploy Reference workflow
- upgrade Antora to 3.1
- reconfigure docs build for local build only
- add patch to support using linked worktree as Antora content source
- remove Antora extensions only needed for the production docs build

.github/actions/algolia-config.json

@@ -1,20 +0,0 @@
-{
-  "index_name": "security-docs",
-  "start_urls": [
-    "https://docs.spring.io/spring-security/reference/"
-  ],
-  "selectors": {
-    "lvl0": {
-      "selector": "//nav[@class='crumbs']//li[@class='crumb'][last()-1]",
-      "type": "xpath",
-      "global": true,
-      "default_value": "Home"
-    },
-    "lvl1": ".doc h1",
-    "lvl2": ".doc h2",
-    "lvl3": ".doc h3",
-    "lvl4": ".doc h4",
-    "text": ".doc p, .doc td.content, .doc th.tableblock"
-  }
-}
-

.github/actions/algolia-deploy.sh

@@ -1,20 +0,0 @@
-#!/bin/bash
-
-HOST="$1"
-HOST_PATH="$2"
-SSH_PRIVATE_KEY="$3"
-SSH_KNOWN_HOST="$4"
-
-
-if [ "$#" -ne 4 ]; then
-  echo -e "not enough arguments USAGE:\n\n$0 \$HOST \$HOST_PATH \$SSH_PRIVATE_KEY \$SSH_KNOWN_HOSTS \n\n" >&2
-  exit 1
-fi
-
-# Use a non-default path to avoid overriding when testing locally
-SSH_PRIVATE_KEY_PATH=~/.ssh/github-actions-docs
-install -m 600 -D /dev/null "$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"

.github/actions/algolia-docsearch-scraper.sh

@@ -1,21 +0,0 @@
-#!/bin/bash
-
-###
-# Docs
-# config.json https://docsearch.algolia.com/docs/config-file
-# Run the crawler https://docsearch.algolia.com/docs/run-your-own/#run-the-crawl-from-the-docker-image
-
-### USAGE
-if [ "$#" -ne 3 ]; then
-  echo -e "not enough arguments USAGE:\n\n$0 \$ALGOLIA_APPLICATION_ID \$ALGOLIA_API_KEY \$CONFIG_FILE\n\n" >&2
-  exit 1
-fi
-
-# Script Parameters
-APPLICATION_ID=$1
-API_KEY=$2
-CONFIG_FILE=$3
-
-#### Script
-script_dir=$(dirname $0)
-docker run -e "APPLICATION_ID=$APPLICATION_ID" -e "API_KEY=$API_KEY" -e "CONFIG=$(cat $CONFIG_FILE | jq -r tostring)" algolia/docsearch-scraper