[improvemnt](script) support custom lib dir to save custom libs

bin/start_be.sh

@@ -107,6 +107,13 @@ if [[ -d "${DORIS_HOME}/lib/hadoop_hdfs/" ]]; then
     done
 fi
 
+# add custome_libs to CLASSPATH
+if [[ -d "${DORIS_HOME}/custom_lib" ]]; then
+    for f in "${DORIS_HOME}/custom_lib"/*.jar; do
+        DORIS_CLASSPATH="${DORIS_CLASSPATH}:${f}"
+    done
+fi
+
 if [[ -n "${HADOOP_CONF_DIR}" ]]; then
     export DORIS_CLASSPATH="${DORIS_CLASSPATH}:${HADOOP_CONF_DIR}"
 fi

bin/start_fe.sh

@@ -176,6 +176,13 @@ for f in "${DORIS_HOME}/lib"/*.jar; do
     CLASSPATH="${f}:${CLASSPATH}"
 done
 
+# add custome_libs to CLASSPATH
+if [[ -d "${DORIS_HOME}/custom_lib" ]]; then
+    for f in "${DORIS_HOME}/custom_lib"/*.jar; do
+        CLASSPATH="${f}:${CLASSPATH}"
+    done
+fi
+
 # make sure the doris-fe.jar is at first order, so that some classed
 # with same qualified name can be loaded priority from doris-fe.jar
 CLASSPATH="${DORIS_FE_JAR}:${CLASSPATH}"

docs/en/docs/lakehouse/faq.md

@@ -199,6 +199,8 @@ under the License.
 
     Search in the hadoop environment hadoop-lzo-*.jar, and put it under "${DORIS_HOME}/fe/lib/",then restart fe.
 
+    Starting from version 2.0.2, this file can be placed in BE's `custom_lib/` directory (if it does not exist, just create it manually) to prevent the file from being lost due to the replacement of the lib directory when upgrading the cluster.
+
 ## HDFS
 
 1. What to do with the`java.lang.VerifyError: xxx` error when accessing HDFS 3.x?

docs/en/docs/lakehouse/multi-catalog/jdbc.md

@@ -791,7 +791,9 @@ DROP CATALOG <catalog_name>;
 
 12. `Non supported character set (add orai18n.jar in your classpath): ZHS16GBK` exception occurs when reading Oracle
 
-    Download [orai18n.jar](https://www.oracle.com/database/technologies/appdev/jdbc-downloads.html) and put it in the lib directory of Doris FE and the lib/java_extensions directory of BE (Doris versions before 2.0 need to be placed in the lib directory of BE).
+    Download [orai18n.jar](https://www.oracle.com/database/technologies/appdev/jdbc-downloads.html) and put it in the lib directory of Doris FE and the `lib/java_extensions/` directory of BE (Doris versions before 2.0 need to be placed in the lib directory of BE).
+
+    Starting from version 2.0.2, this file can be placed in BE's `custom_lib/` directory (if it does not exist, just create it manually) to prevent the file from being lost due to the replacement of the lib directory when upgrading the cluster.
 
 13. `NoClassDefFoundError: net/jpountz/lz4/LZ4Factory` exception occurs when reading Clickhouse data via jdbc catalog.
 

docs/en/docs/lakehouse/multi-catalog/paimon.md

@@ -60,10 +60,13 @@ CREATE CATALOG `paimon_hdfs` PROPERTIES (
 
 #### S3
 
->Note that.
+> Note that.
 >
 > user need download [paimon-s3-0.4.0-incubating.jar](https://repo.maven.apache.org/maven2/org/apache/paimon/paimon-s3/0.4.0-incubating/paimon-s3-0.4.0-incubating.jar)
+>
 > Place it in directory ${DORIS_HOME}/be/lib/java_extensions/preload-extensions and restart be
+>
+> Starting from version 2.0.2, this file can be placed in BE's `custom_lib/` directory (if it does not exist, just create it manually) to prevent the file from being lost due to the replacement of the lib directory when upgrading the cluster.
 
 ```sql
 CREATE CATALOG `paimon_s3` PROPERTIES (

docs/zh-CN/docs/lakehouse/faq.md

@@ -192,6 +192,8 @@ under the License.
 
    去hadoop环境搜索`hadoop-lzo-*.jar`放在`"${DORIS_HOME}/fe/lib/"`目录下并重启fe。
 
+   从 2.0.2 版本起，可以将这个文件放置在BE的 `custom_lib/` 目录下（如不存在，手动创建即可），以防止升级集群时因为 lib 目录被替换而导致文件丢失。
+
 ## HDFS
 
 1. 访问 HDFS 3.x 时报错：`java.lang.VerifyError: xxx`

docs/zh-CN/docs/lakehouse/multi-catalog/jdbc.md

@@ -788,6 +788,8 @@ DROP CATALOG <catalog_name>;
 
     下载 [orai18n.jar](https://www.oracle.com/database/technologies/appdev/jdbc-downloads.html) 并放到 Doris FE 的 lib 目录以及 BE 的 lib/java_extensions 目录 (Doris 2.0 之前的版本需放到 BE 的 lib 目录下) 下即可。
 
+    从 2.0.2 版本起，可以将这个文件放置在BE的 `custom_lib/` 目录下（如不存在，手动创建即可），以防止升级集群时因为 lib 目录被替换而导致文件丢失。
+
 13. 通过jdbc catalog 读取Clickhouse数据出现`NoClassDefFoundError: net/jpountz/lz4/LZ4Factory` 错误信息
 
     可以先下载[lz4-1.3.0.jar](https://repo1.maven.org/maven2/net/jpountz/lz4/lz4/1.3.0/lz4-1.3.0.jar)包，然后放到DorisFE lib 目录以及BE 的 `lib/lib/java_extensions`目录中（Doris 2.0 之前的版本需放到 BE 的 lib 目录下）。

docs/zh-CN/docs/lakehouse/multi-catalog/paimon.md

@@ -60,10 +60,13 @@ CREATE CATALOG `paimon_hdfs` PROPERTIES (
 
 #### S3
 
->注意：
+> 注意：
 >
 > 用户需要手动下载[paimon-s3-0.4.0-incubating.jar](https://repo.maven.apache.org/maven2/org/apache/paimon/paimon-s3/0.4.0-incubating/paimon-s3-0.4.0-incubating.jar)
-> 放在${DORIS_HOME}/be/lib/java_extensions/preload-extensions目录下并重启be
+
+> 放在${DORIS_HOME}/be/lib/java_extensions/preload-extensions目录下并重启be。
+>
+> 从 2.0.2 版本起，可以将这个文件放置在BE的 `custom_lib/` 目录下（如不存在，手动创建即可），以防止升级集群时因为 lib 目录被替换而导致文件丢失。
 
 ```sql
 CREATE CATALOG `paimon_s3` PROPERTIES (