[INLONG-10560][Sort] Support bounded pulsar source

[aloyszhang]

Fixes #10560

Motivation

The pulsar source only supports un-bounded data sources, this pull request aims to add the support for bounded pulsar source.

Modifications

1. define the boundaries for the source
2. make pulsar source support bounded data(this pull request only support time boundaries)

This is worked for offline sync jobs with Flink batch runtime mode.
Every time the Flink batch task begins, set the start and stop timestamp(the publish time of pulsar msg) of the Pulsar source.
The time to finish the batch Flink job is determined by the stop boundary(StopCursor for the Pulsar source).

Note: since the boundaries, especially the stop boundary, are defined by the pulsar message's publish time, the batch Flink job may not be finished if no messages are published into the Pulsar topic.

Verifying this change

(Please pick either of the following options)

• This change is a trivial rework/code cleanup without any test coverage.

Documentation

• Does this pull request introduce a new feature? ( no)

[baomingyu]

+1