Add slim shadowJar variant for key.ui and fix dist build

[wadoon]

Summary

Adds a new configuration to key.ui that produces a slim version of the shadow jar, complementing the existing fat jar:

• Fat jar (unchanged): key-*-exe.jar — everything incl. the optional keyext extensions and examples.zip.
• Slim jar (new): key-*-slim-exe.jar — a minimal executable jar without the optional keyext extension modules (testgen, caching, exploration, slicing, proofmanagement, isabelletranslation) and without the bundled examples.zip.

Implementation

• New slimRuntimeClasspath configuration in key.ui/build.gradle: the full runtimeClasspath minus the six keyext runtime extensions (and their transitive deps such as scala-isabelle/stringtemplate).
• New slimJar ShadowJar task: same wiring as shadowJar (mergeServiceFiles, Main-Class), but built from the slim configuration and excluding examples.zip.
• slimJar is wired into assemble, so a normal build produces both jars.
• Weekly build/deploy workflow (.github/workflows/nightlydeploy.yml) and scripts/jenkins/deployAll.sh now build/upload the slim jar as well.

Fixes

The :dist project referenced the removed key.core.rifl and key.removegenerics modules and was missing a description, which broke Gradle configuration of every build. Both issues are fixed.

Verification

• ./gradlew :key.ui:assemble produces both jars:
  • key-3.1.0-dev-exe.jar (fat, ~58 MB, 22 881 classes)
  • key-3.1.0-dev-slim-exe.jar (slim, ~24 MB, 12 943 classes)
• Slim jar contains no keyext/scala/isabelle/testgen classes and no examples.zip; service files merged with the built-in key.ui/key.core extensions only.
• Smoke test: java -jar key-*-slim-exe.jar --help starts KeY's CLI.