[type:feat] [ISSUE #5615] Datasource support OceanBase.

[VampireAchao]

// Describe your PR here; eg. Fixes #issueNo Resolve #5615 Make sure that:

• [X] You have read the contribution guidelines.
• [X] You submit test cases (unit or integration tests) that back your changes.
• [X] Your local test passed mvn clean install -Dmaven.javadoc.skip=true.

ShenyuAdmin Datasource support OceanBase.

Modify :

• Added the configuration org.apache.shenyu.admin.config.MapperConfig.OceanBaseSQLConfig to ensure PageHelper uses the MySQL dialect.
• Added application-ob.yml with the default OceanBase port, driver, and set spring.integration.jdbc.platform to mysql.

Notice:

The driver com.oceanbase:oceanbase-client in pom.xml is provided by default in ShenyuAdmin. Users need to modify or remove it before use.