[Improve][DataProxy] Clean up useless configuration files in the ConfigManager class

[gosonzhang]

Description

Analyze the implementation of the ConfigManager class[1] and find that some configuration files do not need to be preserved:

1. transfer.properties, not used in the system;
2. dc_mapping.properties, tube_switch.properties, from the perspective of implementation, belong to some original code residues, and there is no document to define its usage, so it is not necessary to keep it;

In addition, for the unused blacklist.properties, it is very helpful for managing the reporting source on the access side. Personally, it needs to expand its use, it will not be deleted.

1. https://github.com/apache/inlong/blob/master/inlong-dataproxy/dataproxy-source/src/main/java/org/apache/inlong/dataproxy/config/ConfigManager.java#L75

InLong Component

InLong DataProxy

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• Yes, I am willing to submit a PR!

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