[rpc] Support Netty Logging at the network layer

[SteNicholas]

Purpose

Linked issue: close #378

Support Netty level logging at the network layer for Fluss. To configure Netty level logging a LogHandler must be added to the channel pipeline. NettyLogger is introduced as a new class which is able to construct a log handler depending on the log level:

• In case of <Logger name="com.alibaba.fluss.rpc.netty.NettyLogger;" level="DEBUG" additivity="false">: a custom log handler is created which does not dump the message contents. This way the log is a bit more compact. Moreover when network level encryption is switched on this level might be sufficient.
• In case of <Logger name="com.alibaba.fluss.rpc.netty.NettyLogger" level="TRACE" additivity="false">: Netty's own log handler is used which dumps the message contents.
• Otherwise (when the logger is not TRACE or DEBUG) the pipeline does not contain a log handler (there is no runtime penalty for the default setting but a long running service must be restarted along with the new log level to have an effect).

Backport:

• [SPARK-36719][CORE] Supporting Netty Logging at the network layer
• [SPARK-45377][CORE] Handle InputStream in NettyLogger

This level of logging proved to be sufficient during debugging some external related problem. Compared with the tcpdump this log lines can be more easily correlated with the Fluss internal calls. Moreover the log layout can be configured to contain the thread names that way for a timeout a busy thread could be identified.

Tests

No.

API and Format

No.

Documentation

No.

[SteNicholas]

Ping @wuchong.

[wuchong]

Nice feature! LGTM.