Removed global domain enabled config

[vytautas-karpavicius]

What changed?
Removed:

• cluster configuration entry: enableGlobalDomain
• dynamic config entry: system.enableGlobalDomain

All places that checked whether global domain is enabled, will treat as it is always enabled.

Removed no longer relevant tests.

Why?
This was already deprecated and was giving warnings when disabled.

[WARN] Local domain is now deprecated. Please update config to enable global domain(ClusterGroupMetadata>EnableGlobalDomain). Global domain of single cluster has zero overhead, but only advantages for future migration and fail over. Please check Cadence documentation for more details.

How did you test it?
Existing tests.

Potential risks

Release notes

Documentation Changes

[coveralls]

Pull Request Test Coverage Report for Build 0180ff15-fd85-44be-95b8-2bf5aea41e1b

• 49 of 66 (74.24%) changed or added relevant lines in 13 files are covered.
• 14 unchanged lines in 8 files lost coverage.
• Overall coverage increased (+0.2%) to 57.01%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
common/persistence/persistence-tests/persistenceTestBase.go	0	2	0.0%
service/worker/service.go	0	2	0.0%
tools/cli/domainUtils.go	0	2	0.0%
service/history/queue/timer_queue_processor.go	12	16	75.0%
service/history/queue/transfer_queue_processor.go	12	19	63.16%

Files with Coverage Reduction	New Missed Lines	%
service/history/execution/mutable_state_task_refresher.go	1	73.42%
service/history/queue/timer_queue_processor.go	1	58.44%
service/history/queue/transfer_queue_processor.go	1	56.92%
tools/cli/domainUtils.go	1	2.11%
common/domain/attrValidator.go	2	84.44%
common/task/weightedRoundRobinTaskScheduler.go	2	89.12%
common/messaging/noop_producer.go	3	0%
common/task/fifoTaskScheduler.go	3	84.54%

Totals
Change from base Build 0180fef5-de8b-494c-b195-5c8dc9d1f4fe:	0.2%
Covered Lines:	83945
Relevant Lines:	147245

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💛 - Coveralls