[KYUUBI #2850][FOLLOWUP] Fix default log4j2 configuration

### _Why are the changes needed?_

Remove `conf/log4j2.properties.template` as it has been replaced by `conf/log4j2.xml.template`
Remove `<ThresholdFilter level="FATAL"/>` in default stdout appender.

### _How was this patch tested?_
- [ ] Add some test cases that check the changes thoroughly including negative and positive cases if possible

- [ ] Add screenshots for manual tests if appropriate

- [ ] [Run test](https://kyuubi.apache.org/docs/latest/develop_tools/testing.html#running-tests) locally before make a pull request

Closes #3000 from pan3793/log4j-followup.

Closes #2850

ccb9dd6 [Cheng Pan] [KYUUBI #2850][FOLLOWUP] Fix default log4j2 configuration

Authored-by: Cheng Pan <chengpan@apache.org>
Signed-off-by: Cheng Pan <chengpan@apache.org>

Author: pan3793

conf/log4j2.properties.template

@@ -24,7 +24,6 @@
         <Console name="stdout" target="SYSTEM_OUT">
             <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} %p %c: %m%n"/>
             <Filters>
-                <ThresholdFilter level="FATAL"/>
                 <RegexFilter regex=".*Thrift error occurred during processing of message.*" onMatch="DENY" onMismatch="NEUTRAL"/>
             </Filters>
         </Console>

conf/log4j2.xml.template

@@ -23,7 +23,6 @@
         <Console name="stdout" target="SYSTEM_OUT">
             <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} %p %c: %m%n"/>
             <Filters>
-                <ThresholdFilter level="FATAL"/>
                 <RegexFilter regex=".*Thrift error occurred during processing of message.*" onMatch="DENY" onMismatch="NEUTRAL"/>
             </Filters>
         </Console>