ci_boost_release: Add highlight.js for Asciidoctor documentation

[julioest]

• Update ci_boost_release.py to configure Asciidoctor to use highlight.js for source code highlighting\n- Document the use of highlight.js in the v4 Dockerfile README\n\nThis addresses the first part of Replace Rouge with highlight.js for code styling boostlook#67 by ensuring the build system is properly configured to use highlight.js with Asciidoctor documentation.

[sdarwin]

Yes this appears correct. (Or at least, following the right tactic). However highlight.js isn't present in the Docker container, right? The pull request should include the updated Dockerfile with highlight.js.
Then I will build the image and upload it to docker hub. and then you could test with the new image. (or even before, if built locally).

There is a factor that may affect things "[boost] Master branch closing for major changes TOMORROW"

Re-base from develop branch to fix a lint error.

[julioest]

Disregard this PR. Seems that my editor, pushed this automatically