Added a hint to the --cache-config-file config option that you not need to specify the configuration folder

Closes #11302

docs/guides/src/main/server/caching.adoc

@@ -99,6 +99,8 @@ To specify your own cache configuration file, enter this command:
 
 <@kc.build parameters="--cache-config-file=my-cache-file.xml"/>
 
+The configuration file is relative to the `conf/` directory.
+
 == Transport stacks
 Transport stacks ensure that distributed cache nodes in a cluster communicate in a reliable fashion.
 Keycloak supports a wide range of transport stacks:

quarkus/runtime/src/main/java/org/keycloak/quarkus/runtime/configuration/mappers/ClusteringPropertyMappers.java

@@ -34,7 +34,8 @@ final class ClusteringPropertyMappers {
                 builder().from("cache-config-file")
                         .mapFrom("cache")
                         .to("kc.spi-connections-infinispan-quarkus-config-file")
-                        .description("Defines the file from which cache configuration should be loaded from.")
+                        .description("Defines the file from which cache configuration should be loaded from. "
+                                + "The configuration file is relative to the 'conf/' directory.")
                         .transformer(new BiFunction<String, ConfigSourceInterceptorContext, String>() {
                             @Override
                             public String apply(String value, ConfigSourceInterceptorContext context) {

quarkus/tests/integration/src/test/resources/org/keycloak/it/cli/approvals/cli/help/HelpCommandTest.testBuildHelp.unix.approved.txt

@@ -29,7 +29,8 @@ Cluster:
                        disables clustering and is intended for development and testing purposes.
                        Default: ispn.
 --cache-config-file <file>
-                     Defines the file from which cache configuration should be loaded from.
+                     Defines the file from which cache configuration should be loaded from. The
+                       configuration file is relative to the 'conf/' directory.
 --cache-stack <stack>
                      Define the default stack to use for cluster communication and node discovery.
                        This option only takes effect if 'cache' is set to 'ispn'. Default: udp.

quarkus/tests/integration/src/test/resources/org/keycloak/it/cli/approvals/cli/help/HelpCommandTest.testBuildHelp.windows.approved.txt

@@ -29,7 +29,8 @@ Cluster:
                        disables clustering and is intended for development and testing purposes.
                        Default: ispn.
 --cache-config-file <file>
-                     Defines the file from which cache configuration should be loaded from.
+                     Defines the file from which cache configuration should be loaded from. The
+                       configuration file is relative to the 'conf/' directory.
 --cache-stack <stack>
                      Define the default stack to use for cluster communication and node discovery.
                        This option only takes effect if 'cache' is set to 'ispn'. Default: udp.
@@ -104,4 +105,4 @@ running this command every time you change a configuration:
 
     $ kc.bat start --auto-build <OPTIONS>
 
-By doing that you have an additional overhead when the server is starting.
+By doing that you have an additional overhead when the server is starting.

quarkus/tests/integration/src/test/resources/org/keycloak/it/cli/approvals/cli/help/HelpCommandTest.testStartDevHelpAll.unix.approved.txt

@@ -21,7 +21,8 @@ Cluster:
                        disables clustering and is intended for development and testing purposes.
                        Default: ispn.
 --cache-config-file <file>
-                     Defines the file from which cache configuration should be loaded from.
+                     Defines the file from which cache configuration should be loaded from. The
+                       configuration file is relative to the 'conf/' directory.
 --cache-stack <stack>
                      Define the default stack to use for cluster communication and node discovery.
                        This option only takes effect if 'cache' is set to 'ispn'. Default: udp.

quarkus/tests/integration/src/test/resources/org/keycloak/it/cli/approvals/cli/help/HelpCommandTest.testStartDevHelpAll.windows.approved.txt

@@ -21,7 +21,8 @@ Cluster:
                        disables clustering and is intended for development and testing purposes.
                        Default: ispn.
 --cache-config-file <file>
-                     Defines the file from which cache configuration should be loaded from.
+                     Defines the file from which cache configuration should be loaded from. The
+                       configuration file is relative to the 'conf/' directory.
 --cache-stack <stack>
                      Define the default stack to use for cluster communication and node discovery.
                        This option only takes effect if 'cache' is set to 'ispn'. Default: udp.