[Improve][Manager] Optimize flink job building and manage procedure

[aloyszhang]

Description

Currently, long-manager builds too many objects like FlinkConfiguration, FlinkService, and FlinkOperation when building and managing Flink jobs.
The reason is, that for every single access of these classes, the manager creates a new object.
See:
https://github.com/apache/inlong/blob/master/inlong-manager/manager-plugins/base/src/main/java/org/apache/inlong/manager/plugin/flink/FlinkService.java#?L73~L75

   public FlinkService(String endpoint) throws Exception {
        FlinkConfiguration flinkConfiguration = new FlinkConfiguration();
        flinkConfig = flinkConfiguration.getFlinkConfig();

https://github.com/apache/inlong/blob/master/inlong-manager/manager-plugins/base/src/main/java/org/apache/inlong/manager/plugin/listener/StartupSortListener.java#L143~L144

            FlinkService flinkService = new FlinkService(flinkInfo.getEndpoint());
            FlinkOperation flinkOperation = new FlinkOperation(flinkService);

InLong Component

InLong Manager

Are you willing to submit PR?

• Yes, I am willing to submit a PR!

Code of Conduct

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