Extract caching logic into a separate gradle-actions-caching component (#885)

With this change, the caching functionality of `setup-gradle` and
`dependency-submission` is now provided by `gradle-actions-caching`, a
closed-source library distributed under our [Terms of
Use](https://gradle.com/legal/terms-of-use/). The rest of the action
implementation remains open source.

Using `setup-gradle` or `dependency-submission` with caching enabled
involves loading and using the `gradle-actions-caching` component,
requiring acceptance of the [Terms of
Use](https://gradle.com/legal/terms-of-use/). There are no functional
changes to caching provided by these actions: all workflows will
continue to function as before.

The non-caching aspects of action implementation remain open source. By
running these actions with caching disabled they can be used without
ever loading `gradle-actions-caching` or accepting the license terms.

Supporting the caching infrastructure in this project requires a
substantial engineering investment by Gradle Technologies, which we can
sustain thanks to Develocity, our commercial offering. Caching
technologies are a core part of the Develocity offering, and the caching
in `setup-gradle` fits squarely in that space.

This licensing change lets us continue to build advanced capabilities
that go beyond what we would offer as open source. Proper
production-ready Configuration Cache support will be the first
capability. Improving build performance for self-hosted runners will
follow.

We may introduce functionality restrictions in future updates. However,
caching functionality will remain free for public repositories.
We have a long-standing commitment to open source, as maintainers of
Gradle Build Tool, and by [sponsoring the open source
community](https://gradle.com/oss-sponsored-by-develocity/) with free
Develocity licenses. Public repositories are primarily used by open
source projects, and we remain committed to supporting them.

- Implementation of caching logic to save and restore Gradle User Home
content has been removed, replaced by the `gradle-actions-caching`
component.
- The `@actions/caching` library is still used to cache Gradle
distributions that are downloaded and provisioned by `setup-gradle`.
This PR updates to the latest version of `@actions/caching`, and removes
the patch that is no longer required.
- License notices are now displayed in documentation, logs and the
generated Job Summary.

docs/setup-gradle.md

@@ -2,6 +2,19 @@
 
 This GitHub Action can be used to configure Gradle for optimal execution on any platform supported by GitHub Actions.
 
+> [!IMPORTANT]
+> ## Licensing notice
+>
+> The software in this repository is licensed under the [MIT License](LICENSE).
+>
+> The caching functionality in this project has been extracted into `gradle-actions-caching`, a proprietary commercial component that is not covered by the MIT License for this repository. 
+> The bundled `gradle-actions-caching` component is licensed and governed by a separate license, available at https://gradle.com/legal/terms-of-use/.
+>
+> The `gradle-actions-caching` component is used only when caching is enabled and is not loaded or used when caching is disabled.
+>
+> Use of the `gradle-actions-caching` component is subject to a separate license, available at https://gradle.com/legal/terms-of-use/. 
+> If you do not agree to these license terms, do not use the `gradle-actions-caching` component.
+
 ## Why use the `setup-gradle` action?
 
 It is possible to directly invoke Gradle in your workflow, and the `actions/setup-java@v4` action provides a simple way to cache Gradle dependencies.
@@ -933,4 +946,3 @@ Each of the plugins is signed by Gradle, and you can simply add the following sn
    </trusted-key>
 </trusted-keys>
 ```
-