Add open-source 'basic' cache provider and revamp licensing documentation (#930)

## Summary

- **New `basic` cache provider**: Adds an open-source (MIT-licensed)
caching implementation built on `@actions/cache` as an alternative to
the proprietary Enhanced Caching. Users can opt in with `cache-provider:
basic` on both `setup-gradle` and `dependency-submission` actions.
- **Revamped licensing & distribution docs**: Replaces the verbose
licensing notice block (previously shown in README, docs, and logs) with
a friendlier callout and a new dedicated
[DISTRIBUTION.md](./DISTRIBUTION.md) covering component licensing, usage
tiers, data privacy ("Safe Harbor"), and opt-out instructions.
- **Improved messaging**: Enhanced Caching and Basic Caching each
display concise, informative log messages and job summary notes instead
of the previous wall-of-text license warning.
- **New integration tests**: Adds `integ-test-basic-cache-provider.yml`
workflow that seeds and verifies the basic cache provider across
platforms, plus unit tests for `BasicCacheService` and `getCacheService`
selection logic.
- **CI workflow reorganization**: Dependency-submission integration
tests extracted into their own reusable suite
(`suite-integ-test-dependency-submission.yml`); sample project tests
moved into the caching suite.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/suite-integ-test-other.yml

@@ -20,33 +20,6 @@ jobs:
       runner-os: '${{ inputs.runner-os }}'
       skip-dist: ${{ inputs.skip-dist }}
 
-  dependency-graph:
-    if: ${{ ! github.event.pull_request.head.repo.fork }}
-    uses: ./.github/workflows/integ-test-dependency-graph.yml
-    permissions:
-      contents: write
-    with:
-      runner-os: '${{ inputs.runner-os }}'
-      skip-dist: ${{ inputs.skip-dist }}
-
-  dependency-submission:
-    if: ${{ ! github.event.pull_request.head.repo.fork }}
-    uses: ./.github/workflows/integ-test-dependency-submission.yml
-    permissions:
-      contents: write
-    with:
-      runner-os: '${{ inputs.runner-os }}'
-      skip-dist: ${{ inputs.skip-dist }}
-
-  dependency-submission-failures:
-    if: ${{ ! github.event.pull_request.head.repo.fork }}
-    uses: ./.github/workflows/integ-test-dependency-submission-failures.yml
-    permissions:
-      contents: write
-    with:
-      runner-os: '${{ inputs.runner-os }}'
-      skip-dist: ${{ inputs.skip-dist }}
-
   develocity-injection:
     if: ${{ ! github.event.pull_request.head.repo.fork }}
     uses: ./.github/workflows/integ-test-inject-develocity.yml
@@ -61,18 +34,6 @@ jobs:
       runner-os: '${{ inputs.runner-os }}'
       skip-dist: ${{ inputs.skip-dist }}
 
-  sample-kotlin-dsl:
-    uses: ./.github/workflows/integ-test-sample-kotlin-dsl.yml
-    with:
-      runner-os: '${{ inputs.runner-os }}'
-      skip-dist: ${{ inputs.skip-dist }}
-
-  sample-gradle-plugin:
-    uses: ./.github/workflows/integ-test-sample-gradle-plugin.yml
-    with:
-      runner-os: '${{ inputs.runner-os }}'
-      skip-dist: ${{ inputs.skip-dist }}
-
   toolchain-detection:
     uses: ./.github/workflows/integ-test-detect-toolchains.yml
     with: