markup/asciidocext: Improve Asciidoctor integration

Fixes an issue where improper attribute derivation from the page's
relative permalink caused failures with `outdir`, `imagesoutdir`, and
`imagesdir` when `markup.asciidocext.workingFolderCurrent` is enabled.
The updated logic now correctly handles:

- Multi-byte characters
- Multilingual multi-host sites
- Site builds from a subdirectory
- Pages using ugly URLs

Supports diagram caching as implemented in v3.1.0 of the asciidoctor-diagram
extension:

- Enables caching by default
- Sets default cache location to the compiled value of caches.misc.dir

Reduces duration of integration tests by:

- Generating GoAT diagrams instead of Ditaa diagrams
- Taking advantage of asciidoctor-diagram caching

Closes #9202
Closes #10183
Closes #10473
Closes #14160

.github/workflows/test.yml

@@ -46,19 +46,12 @@ jobs:
         uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
         with:
           ruby-version: "3.4.5"
-      - name: Install gems
+      - name: Install Ruby gems
         run: |
           gem install asciidoctor -v "2.0.26"
           gem install asciidoctor-diagram -v "3.1.0"
-          gem install asciidoctor-diagram-ditaamini -v "1.0.3"
       - name: Install GoAT
         run: go install github.com/blampe/goat/cmd/goat@177de93b192b8ffae608e5d9ec421cc99bf68402
-      - name: Install Java # required by asciidoctor-diagram-ditaamini
-        uses: actions/setup-java@dded0888837ed1f317902acf8a20df0ad188d165 # v5.0.0
-        with:
-          distribution: temurin
-          java-version: "25"
-          java-package: jre
       - name: Install Python
         uses: actions/setup-python@e797f83bcb11b83ae66e0230d6156d7c80228e7c # v6.0.0
         with: