Feat: Use Besu plugin Gradle plugin

[fab-10]

Note

Migrates the build to Besu plugin Gradle plugins, removes custom distro/legacy configs, simplifies dependencies, and updates test packaging to use distZip.

• Build/Gradle:
  • Adopt net.consensys.besu-plugin-library and net.consensys.besu-plugin-distribution in root and modules; add pluginManagement repo in settings.gradle.
  • Remove legacy configs/tasks: gradle/allprojects.gradle, gradle/common-dependencies.gradle, gradle/dist.gradle; drop custom download plugin usage.
  • Switch build alias and tasks from distPlugin to distZip; update copyTracerPlugin to unzip distZip output.
  • Trim repository config to core Besu and MavenCentral; add besuRepo property.
• Modules:
  • plugins: use distribution plugin; define jar manifest and distributions { main } with distributionIdentifier.
  • arithmetization: streamline dependencies (keep gnark, jackson-yaml), add JUnit/AssertJ test deps; keep manifest attrs.
  • reference-tests and testing: apply library plugin; depend on :arithmetization (and :testing where needed); add minimal test deps.
• Java/Tooling:
  • Configure Java via java {} with source/target 21 and consistentResolution.useCompileClasspathVersions().
  • Sonar setup retained; minor cleanup of root buildscript ext.

^{Written by Cursor Bugbot for commit 3b8c7e1. This will update automatically on new commits. Configure here.}