[AMORO-3404] Correct the description about MySQL usage

The lincense of MySQL is incompatible with Apache Lincese, we need to correct the descriptions

This closes apache/amoro#3403

Author: klion26

amoro-docs/content/admin-guides/deployment-on-kubernetes.md

@@ -157,16 +157,16 @@ ingress:
 ### Configure the database.
 
 AMS default is to use Derby database for storage. When the pod is destroyed, the data will also disappear.
-In production environments, we recommend using MySQL as the storage for system data.
+In production environments, we recommend using a RDBMS as the storage for system data, you can ref to [Database Configuration](/deployment/#configure-system-database) for more detail.
 
 ```yaml
 amoroConf: 
   database:
-    type: mysql
-    driver: com.mysql.cj.jdbc.Driver
-    url: <jdbc-uri>
-    username: <mysql-user>
-    password: <mysql-password>
+    type: ${your_database_type}
+    driver: ${your_database_driver}
+    url: ${your_jdbc_url}
+    username: ${your_username}
+    password: ${your_password}
 ```
 
 

amoro-docs/content/admin-guides/deployment.md

@@ -31,8 +31,7 @@ You can choose to download the stable release package from [download page](../..
 ## System requirements
 
 - Java 8 is required.
-- Optional: MySQL 5.5 or higher
-- Optional: PostgreSQL 14.x or higher
+- Optional: A RDBMS (PostgreSQL 14.x or higher, MySQL 5.5 or higher)
 - Optional: ZooKeeper 3.4.x or higher
 
 ## Download the distribution
@@ -99,38 +98,25 @@ Make sure the port is not used before configuring it.
 
 ### Configure system database
 
-You can use MySQL/PostgreSQL as the system database instead of the default Derby.
+Amoro used `Derby` as the backend storage default, so you can use `Derby` directly without any additional configuration. 
 
-If you would like to use MySQL as the system database, you need to manually download the [MySQL JDBC Connector](https://repo1.maven.org/maven2/com/mysql/mysql-connector-j/8.1.0/mysql-connector-j-8.1.0.jar)
-and move it into the `{AMORO_HOME}/lib/` directory. You can use the following command to complete these operations:
-```shell
-$ cd ${AMORO_HOME}
-$ MYSQL_JDBC_DRIVER_VERSION=8.0.30
-$ wget https://repo1.maven.org/maven2/mysql/mysql-connector-java/${MYSQL_JDBC_DRIVER_VERSION}/mysql-connector-java-${MYSQL_JDBC_DRIVER_VERSION}.jar
-$ mv mysql-connector-java-${MYSQL_JDBC_DRIVER_VERSION}.jar lib
-```
+You can also configure a relational backend storage as you needed.
+
+> If you would like to use MySQL as the system database, you need to manually download the [MySQL JDBC Connector](https://repo1.maven.org/maven2/com/mysql/mysql-connector-j/8.1.0/mysql-connector-j-8.1.0.jar)
+and move it into the `${AMORO_HOME}/lib/` directory.
 
-Create an empty database in MySQL/PostgreSQL, then AMS will automatically create tables in this MySQL/PostgreSQL database when it first started.
+You need to create an empty database in the RDBMS before to start the server, then AMS will automatically create tables in the database when it first started.
 
-One thing you need to do is Adding MySQL/PostgreSQL configuration under `config.yaml` of Ams:
+One thing you need to do is adding configuration under `config.yaml` of Ams:
 
 ```yaml
-# MySQL
 ams:
   database:
-    type: mysql
-    jdbc-driver-class: com.mysql.cj.jdbc.Driver
-    url: jdbc:mysql://127.0.0.1:3306/amoro?useUnicode=true&characterEncoding=UTF8&autoReconnect=true&useAffectedRows=true&allowPublicKeyRetrieval=true&useSSL=false
-    username: root
-    password: root
-# PostgreSQL
-#ams:
-#  database:
-#    type: postgres
-#    jdbc-driver-class: org.postgresql.Driver
-#    url: jdbc:postgresql://127.0.0.1:5432/amoro
-#    username: user
-#    password: passwd
+    type: ${database_type} # postgres or mysql
+    jdbc-driver-class: ${your_driver_name}
+    url: ${your_jdbc_url}
+    username: ${your_username}
+    password: ${your_password}
 ```
 
 ### Configure high availability
@@ -296,7 +282,7 @@ $ bin/ams.sh stop
 
 ### Upgrade system databases
 
-You can find all the upgrade SQL scripts under `{AMORO_HOME}/conf/mysql/` with name pattern `upgrade-a.b.c-to-x.y.z.sql`.
+You can find all the upgrade SQL scripts under `${AMORO_HOME}/conf/${db_type}/` with name pattern `upgrade-a.b.c-to-x.y.z.sql`.
 Execute the upgrade SQL scripts one by one to your system database based on your starting and target versions.
 
 ### Replace all libs and plugins

amoro-docs/content/concepts/catalogs.md

@@ -34,7 +34,7 @@ the multi-catalog feature can be used to support SQL across data sources, such a
 
 ```SQL
 SELECT c.ID, c.NAME, c.AGE, o.AMOUNT
-FROM MYSQL.ONLINE.CUSTOMERS c JOIN HIVE.OFFLINE.ORDERS o
+FROM ${CATALOG_A}.ONLINE.CUSTOMERS c JOIN ${CATALOG_B}.OFFLINE.ORDERS o
 ON (c.ID = o.CUSTOMER_ID)
 ```