Add the ability to set logging levels

[tpiperatgod]

(If this PR fixes a github issue, please add Fixes #<xyz>.)

Fixes #413

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Master Issue: #

Motivation

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Modifications

For Java and Python functions, I provide two ways for the user to set the logging level.

• Set the log level directly

  apiVersion: compute.functionmesh.io/v1alpha1
  kind: Function
  metadata:
    name: function-sample
    namespace: default
  spec:
    java:
      log:
        level: "debug"

• Provide custom logging configuration file

  apiVersion: compute.functionmesh.io/v1alpha1
  kind: Function
  metadata:
    name: function-sample
    namespace: default
  spec:
    java:
      log:
        logConfig:
          name: "java-log-config-cm"
          key: "java-config-xml"
  ---
  apiVersion: v1
  kind: ConfigMap
  metadata:
    name: java-log-config-cm
  data:
    java-config-xml: |
      <Configuration>
          <name>pulsar-functions-kubernetes-instance</name>
          <monitorInterval>30</monitorInterval>
          <Properties>
              <Property>
                  <name>pulsar.log.level</name>
                  <value>DEBUG</value>
              </Property>
              <Property>
                  <name>bk.log.level</name>
                  <value>DEBUG</value>
              </Property>
          </Properties>
          <Appenders>
              <Console>
                  <name>Console</name>
                  <target>SYSTEM_OUT</target>
                  <PatternLayout>
                      <Pattern>%d{ISO8601_OFFSET_DATE_TIME_HHMM} [%t] %-5level %logger{36} - %msg%n</Pattern>
                  </PatternLayout>
              </Console>
          </Appenders>
          <Loggers>
              <Logger>
                  <name>org.apache.pulsar.functions.runtime.shaded.org.apache.bookkeeper</name>
                  <level>${sys:bk.log.level}</level>
                  <additivity>false</additivity>
                  <AppenderRef>
                      <ref>Console</ref>
                  </AppenderRef>
              </Logger>
              <Root>
                  <level>${sys:pulsar.log.level}</level>
                  <AppenderRef>
                      <ref>Console</ref>
                      <level>${sys:pulsar.log.level}</level>
                  </AppenderRef>
              </Root>
          </Loggers>
      </Configuration>
  

For Go functions, currently, only direct log level setting is supported.

Verifying this change

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

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• Added integration tests for end-to-end deployment with large payloads (10MB)
• Extended integration test for recovery after broker failure

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