KYLIN-3820 Add a curator-based scheduler

[Wayne1c]

No description provided.

[asfgit]

Can one of the admins verify this patch?

[Aaaaaaron]

retest this please

[coveralls]

Pull Request Test Coverage Report for Build 4176

• 114 of 177 (64.41%) changed or added relevant lines in 4 files are covered.
• 2 unchanged lines in 2 files lost coverage.
• Overall coverage increased (+0.1%) to 27.06%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
core-common/src/main/java/org/apache/kylin/common/KylinConfigBase.java	0	4	0.0%
core-job/src/main/java/org/apache/kylin/job/impl/curator/CuratorLeaderSelector.java	30	43	69.77%
core-common/src/main/java/org/apache/kylin/common/ServerMode.java	0	17	0.0%
core-job/src/main/java/org/apache/kylin/job/impl/curator/CuratorScheduler.java	84	113	74.34%

Files with Coverage Reduction	New Missed Lines	%
core-dictionary/src/main/java/org/apache/kylin/dict/lookup/cache/RocksDBLookupTable.java	1	81.08%
server-base/src/main/java/org/apache/kylin/rest/util/QueryRequestLimits.java	1	47.62%

Totals
Change from base Build 4170:	0.1%
Covered Lines:	18836
Relevant Lines:	69609

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💛 - Coveralls