Make ConfigData Resolvers/Loaders public

Change the visibility of our own ConfigDataLocationResolver and
ConfigDataLoader classes so that they can be created outside of
`spring.factories`.

Closes gh-23434

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigTreeConfigDataLoader.java

@@ -27,8 +27,9 @@ import org.springframework.boot.env.ConfigTreePropertySource;
  *
  * @author Madhura Bhave
  * @author Phillip Webb
+ * @since 2.4.0
  */
-class ConfigTreeConfigDataLoader implements ConfigDataLoader<ConfigTreeConfigDataLocation> {
+public class ConfigTreeConfigDataLoader implements ConfigDataLoader<ConfigTreeConfigDataLocation> {
 
 	@Override
 	public ConfigData load(ConfigDataLoaderContext context, ConfigTreeConfigDataLocation location) throws IOException {

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigTreeConfigDataLocation.java

@@ -28,9 +28,10 @@ import org.springframework.util.Assert;
  *
  * @author Madhura Bhave
  * @author Phillip Webb
+ * @since 2.4.0
  * @see ConfigTreePropertySource
  */
-class ConfigTreeConfigDataLocation extends ConfigDataLocation {
+public class ConfigTreeConfigDataLocation extends ConfigDataLocation {
 
 	private final Path path;
 

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigTreeConfigDataLocationResolver.java

@@ -24,8 +24,9 @@ import java.util.List;
  *
  * @author Madhura Bhave
  * @author Phillip Webb
+ * @since 2.4.0
  */
-class ConfigTreeConfigDataLocationResolver implements ConfigDataLocationResolver<ConfigTreeConfigDataLocation> {
+public class ConfigTreeConfigDataLocationResolver implements ConfigDataLocationResolver<ConfigTreeConfigDataLocation> {
 
 	private static final String PREFIX = "configtree:";
 

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/config/ResourceConfigDataLoader.java

@@ -25,8 +25,9 @@ import org.springframework.core.io.Resource;
  *
  * @author Phillip Webb
  * @author Madhura Bhave
+ * @since 2.4.0
  */
-class ResourceConfigDataLoader implements ConfigDataLoader<ResourceConfigDataLocation> {
+public class ResourceConfigDataLoader implements ConfigDataLoader<ResourceConfigDataLocation> {
 
 	@Override
 	public ConfigData load(ConfigDataLoaderContext context, ResourceConfigDataLocation location) throws IOException {

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/config/ResourceConfigDataLocation.java

@@ -33,8 +33,9 @@ import org.springframework.util.Assert;
  *
  * @author Madhura Bhave
  * @author Phillip Webb
+ * @since 2.4.0
  */
-class ResourceConfigDataLocation extends ConfigDataLocation {
+public class ResourceConfigDataLocation extends ConfigDataLocation {
 
 	private final String name;
 

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/config/ResourceConfigDataLocationResolver.java

@@ -50,8 +50,10 @@ import org.springframework.util.StringUtils;
  *
  * @author Madhura Bhave
  * @author Phillip Webb
+ * @since 2.4.0
  */
-class ResourceConfigDataLocationResolver implements ConfigDataLocationResolver<ResourceConfigDataLocation>, Ordered {
+public class ResourceConfigDataLocationResolver
+		implements ConfigDataLocationResolver<ResourceConfigDataLocation>, Ordered {
 
 	private static final String PREFIX = "resource:";
 
@@ -83,7 +85,7 @@ class ResourceConfigDataLocationResolver implements ConfigDataLocationResolver<R
 	 * @param binder a binder backed by the initial {@link Environment}
 	 * @param resourceLoader a {@link ResourceLoader} used to load resources
 	 */
-	ResourceConfigDataLocationResolver(Log logger, Binder binder, ResourceLoader resourceLoader) {
+	public ResourceConfigDataLocationResolver(Log logger, Binder binder, ResourceLoader resourceLoader) {
 		this.logger = logger;
 		this.propertySourceLoaders = SpringFactoriesLoader.loadFactories(PropertySourceLoader.class,
 				getClass().getClassLoader());