Change from python to python3 in fe-core module

[monkeyboy123]

Enhancement

In most enviroment, there exits python2 and python3 env,python always refer to python2, maybe it is a good choice to choose python3 instead of python, as it can report error details, rather than erorr like this:

ERROR] starrocks/fe/fe-core/src/main/java/com/starrocks/qe/StmtExecutor.java:[75,28] cannot find symbol
[ERROR]   symbol:   class Version
[ERROR]   location: package com.starrocks.common
[ERROR] starrocks/fe/fe-core/src/main/java/com/starrocks/system/HeartbeatMgr.java:[44,28] cannot find symbol
[ERROR]   symbol:   class Version
[ERROR]   location: package com.starrocks.common
[ERROR] starrocks/fe/fe-core/src/main/java/com/starrocks/load/streamload/StreamLoadTask.java:[27,28] cannot find symbol
[ERROR]   symbol:   class Version
[ERROR]   location: package com.starrocks.common
[ERROR] starrocks/fe/fe-core/src/main/java/com/starrocks/connector/hive/HiveMetastoreApiConverter.java:[31,28] cannot find symbol
[ERROR]   symbol:   class Version
[ERROR]   location: package com.starrocks.common
[ERROR] starrocks/fe/fe-core/src/main/java/com/starrocks/StarRocksFE.java:[43,28] cannot find symbol
[ERROR]   symbol:   class Version
[ERROR]   location: package com.starrocks.common
[ERROR] starrocks/fe/fe-core/src/main/java/com/starrocks/load/loadv2/LoadLoadingTask.java:[44,28] cannot find symbol
[ERROR]   symbol:   class Version
[ERROR]   location: package com.starrocks.common
[ERROR] starrocks/fe/fe-core/src/main/java/com/starrocks/http/action/IndexAction.java:[38,28] cannot find symbol
[ERROR]   symbol:   class Version
[ERROR]   location: package com.starrocks.common
[ERROR] starrocks/fe/fe-core/src/main/java/com/starrocks/http/rest/FeatureAction.java:[17,28] cannot find symbol
[ERROR]   symbol:   class Version
[ERROR]   location: package com.starrocks.common
[ERROR] starrocks/fe/fe-core/src/main/java/com/starrocks/sql/optimizer/dump/QueryDumpSerializer.java:[29,28] cannot find symbol
[ERROR]   symbol:   class Version
[ERROR]   location: package com.starrocks.common
[ERROR] starrocks/fe/fe-core/src/main/java/com/starrocks/qe/GlobalVariable.java:[39,28] cannot find symbol
[ERROR]   symbol:   class Version
[ERROR]   location: package com.starrocks.common
[ERROR] starrocks/fe/fe-core/src/main/java/com/starrocks/http/rest/BootstrapFinishAction.java:[41,28] cannot find symbol
[ERROR]   symbol:   class Version
[ERROR]   location: package com.starrocks.common