Update With Template Changes

[programming-wolf]

• Remove redundant logo
• Remove ifdef::backend-pdf
• Update docs/images/isaqb-logo.jpg
• Update Asciidoctor stuff (build.gradle + Gradle + workflows)
• Add changelog file + adjust workflows + remove document.version file
• Add support for Release Candidate index page
• Reference new license/copyright submodule
• Update PDF theme
• After merging this PR into main: Build Results will be added to each pull request.

[alxlo]

Big thanks Ben!