Adding logger utils and allow change logger level at runtime

[xiangfu0]

Allow change logger level at runtime.
APIs:

1. Fetch all the loggers:

GET /loggers

2. Fetch logger information:

GET /loggers/${loggerName}

3. Update logger level:

PUT /loggers/${loggerName}?level=${logLevel}

Sample usage:

➜  ~ curl -X GET -H "accept: application/json" localhost:8000/loggers
["root","org.reflections","org.apache.pinot.tools.admin"]
➜  ~ curl -X GET -H "accept: application/json" localhost:8000/loggers/root
{"filter":null,"level":"INFO","name":"root"}
➜  ~ curl -X GET -H "accept: application/json" localhost:8000/loggers
["root","org.reflections","org.apache.pinot.tools.admin"]
➜  ~ curl -X GET -H "accept: application/json" localhost:8000/loggers/root
{"filter":null,"level":"INFO","name":"root"}
➜  ~ curl -X PUT -H "accept: application/json" localhost:8000/loggers/root?level=DEBUG
{"filter":null,"level":"DEBUG","name":"root"}
➜  ~ curl -X GET -H "accept: application/json" localhost:8000/loggers/root
{"filter":null,"level":"DEBUG","name":"root"}
➜  ~ curl -X PUT -H "accept: application/json" localhost:8000/loggers/root?level=ERROR
{"filter":null,"level":"ERROR","name":"root"}
➜  ~ curl -X GET -H "accept: application/json" localhost:8000/loggers/root
{"filter":null,"level":"ERROR","name":"root"}

[codecov-commenter]

Codecov Report

Merging #9180 (5395c67) into master (449f89a) will increase coverage by 41.48%.
The diff coverage is 45.45%.

@@              Coverage Diff              @@
##             master    #9180       +/-   ##
=============================================
+ Coverage     28.49%   69.98%   +41.48%     
- Complexity       53     4756     +4703     
=============================================
  Files          1836     1852       +16     
  Lines         98103    98760      +657     
  Branches      14897    15021      +124     
=============================================
+ Hits          27956    69113    +41157     
+ Misses        67460    24773    -42687     
- Partials       2687     4874     +2187     

Flag	Coverage Δ
integration1	26.20% <0.00%> (-0.16%)	⬇️
integration2	24.82% <0.00%> (-0.02%)	⬇️
unittests1	67.14% <92.59%> (?)
unittests2	15.26% <0.00%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
.../pinot/broker/api/resources/PinotBrokerLogger.java	0.00% <0.00%> (ø)
...ontroller/api/resources/PinotControllerLogger.java	0.00% <0.00%> (ø)
.../pinot/minion/api/resources/PinotMinionLogger.java	0.00% <0.00%> (ø)
.../pinot/server/api/resources/PinotServerLogger.java	0.00% <0.00%> (ø)
...ava/org/apache/pinot/common/utils/LoggerUtils.java	92.59% <92.59%> (ø)
...ntroller/helix/core/minion/TaskMetricsEmitter.java	34.88% <0.00%> (-51.17%)	⬇️
...re/query/reduce/SelectionOnlyStreamingReducer.java	52.94% <0.00%> (-28.02%)	⬇️
...n/java/org/apache/pinot/common/utils/URIUtils.java	66.66% <0.00%> (-7.41%)	⬇️
...core/operator/filter/predicate/PredicateUtils.java	68.18% <0.00%> (-5.90%)	⬇️
...not/broker/broker/helix/ClusterChangeMediator.java	75.26% <0.00%> (-5.38%)	⬇️
... and 1293 more

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[Jackie-Jiang]

Can you please add some tests for the LoggerUtils?
We want to test the following things:

1. The expected return for each method
2. Whether the already initialized logger can be updated

[Jackie-Jiang]

LGTM otherwise