Introduce value alias for cacheNames in @⁠CacheConfig

Prior to this commit @⁠CacheConfig did not have a `value` attribute
alias for `cacheNames`, even though the rest of the cache-related
annotations (such as @⁠Cacheable, @⁠CachePut, etc.) do have a `value` /
`cacheNames` alias pair.

To address that inconsistency, this commit introduces a `value` alias
for `cacheNames` in @⁠CacheConfig as well.

See gh-35096
Closes gh-35152

spring-context-support/src/test/java/org/springframework/cache/caffeine/CaffeineReactiveCachingTests.java

@@ -129,7 +129,7 @@ class CaffeineReactiveCachingTests {
 	}
 
 
-	@CacheConfig(cacheNames = "first")
+	@CacheConfig("first")
 	static class ReactiveCacheableService {
 
 		private final AtomicLong counter = new AtomicLong();