* Enhence the usabilities
1. Add metrics to monitor transactions and steaming load process in BE.
2. Modify BE config 'result_buffer_cancelled_interval_time' to 300s.
3. Modify FE config 'enable_metric_calculator' to true.
4. Add more log for tracing broker load process.
5. Modify the query report process, to cancel query immediately if some instance failed.
* Fix bugs
1. Avoid NullPointer when enabling colocation join with broker load
2. Return immediately when pull load task coordinator execution failed
Added: Support getting column size and precision info of table or view using JDBC.
Updated: Change the promethues type name GAUGE to lowercase, to fit the latest promethues version.
Updated: Backend ip saved in FE will be compared with BE's local ip when doing heartbeat, to avoid false positive heartbeat response.
Updated: Using version_num of tablet instead of calculating nice value to select cumulative compaction candicates.
Fixed: Predicates should not be pushed down to subquery which contains limit clause.
Fixed: Fix the formula of calculating BE load score.
Fixed: Fix a bug that in some edge cases, non-master Fontend may wait for a unnecessary long timeout after forwarding cmd to Master FE.
Fixed: A bug that granting privs on more than one table does not work.
Fixed: Support 'Insert into' table which contains HLL columns.
Fixed: ExportStmt' toSql() method may throw NullPointer Exception if table does not exist.
Fixed: Remove unnecessary 'get capacity' operation to avoid IO impact.
Internal commit id: merge to c16bd603a53dfe2089ff95704c698a738c317792
