[Java] Add session_dir as temp_dir for logs, socket files like Python (#7044)

* Support

* Add gcs_server support

* Fix ut

* Fix

* Remove unused py code

* Fix linting

* Fix cross language ci

* Fix CI

* Add docstring

* Fix

* Fix linting

* Add a singleton for config

* Refine

* fix

* Fix

* linting

* Remove FileUnit

* Fix

* Fix

* Fix

* Update java/runtime/src/main/java/org/ray/runtime/config/RayConfig.java

Co-Authored-By: Hao Chen <chenh1024@gmail.com>

* Fix streaming singleprocess CI

* Fix checkstyle

Co-authored-by: Hao Chen <chenh1024@gmail.com>

java/runtime/src/main/resources/ray.default.conf

@@ -32,7 +32,8 @@ ray {
   }
 
   // Root dir of log files.
-  log-dir: /tmp/ray/logs
+  // If this is not set, the default log-dir will be `${temp-dir}/session_xxx/logs`.
+  log-dir: ""
 
   // If true, output of worker processes will be redirected to log files.
   // Otherwise, output will be printed to console.
@@ -74,8 +75,9 @@ ray {
   // Object store configurations
   // ----------------------------
   object-store {
-    // RPC socket name of object store
-    socket-name: /tmp/ray/sockets/object_store
+    // RPC socket name of object store.
+    // If this is not set, the default name will be `${temp-dir}/session_xxx/sockets/object_store`.
+    socket-name: ""
     // Initial size of the object store.
     size: 10 MB
   }
@@ -84,8 +86,9 @@ ray {
   // Raylet configurations
   // ----------------------------
   raylet {
-    // RPC socket name of Raylet
-    socket-name: /tmp/ray/sockets/raylet
+    // RPC socket name of Raylet.
+    // If this is not set, the default name will be `${temp-dir}/session_xxx/sockets/raylet`.
+    socket-name: ""
     // Listening port for node manager.
     node-manager-port: 0