Add experimental support for cache-cleanup

- Includes basic implementation as `CacheCleaner`
- Integration test that checks unused files are removed:
  - Downloaded dependencies
  - Local build cache entries
  - Wrapper distributions

src/cache-utils.ts

@@ -16,6 +16,7 @@ const CACHE_DISABLED_PARAMETER = 'cache-disabled'
 const CACHE_READONLY_PARAMETER = 'cache-read-only'
 const CACHE_WRITEONLY_PARAMETER = 'cache-write-only'
 const STRICT_CACHE_MATCH_PARAMETER = 'gradle-home-cache-strict-match'
+const CACHE_CLEANUP_ENABLED_PARAMETER = 'gradle-home-cache-cleanup'
 const CACHE_DEBUG_VAR = 'GRADLE_BUILD_ACTION_CACHE_DEBUG_ENABLED'
 
 const CACHE_KEY_PREFIX_VAR = 'GRADLE_BUILD_ACTION_CACHE_KEY_PREFIX'
@@ -46,6 +47,10 @@ export function isCacheDebuggingEnabled(): boolean {
     return process.env[CACHE_DEBUG_VAR] ? true : false
 }
 
+export function isCacheCleanupEnabled(): boolean {
+    return core.getBooleanInput(CACHE_CLEANUP_ENABLED_PARAMETER)
+}
+
 /**
  * Represents a key used to restore a cache entry.
  * The Github Actions cache will first try for an exact match on the key.