Add peer provider plugin registration

[mantas-sidlauskas]

What changed?
Adding peer provider plugin registration code.

Why?
This code is going to be used to load external peer provider plugin. Peer provider plugin will provide an easy way to replace ringpop with another technology.

How did you test it?

Potential risks
None, this code is noop right now.

Related #5593

[coveralls]

Pull Request Test Coverage Report for Build 018f0eb5-70f7-47c9-a502-c4c524e5014f

Details

• 20 of 22 (90.91%) changed or added relevant lines in 1 file are covered.
• 21 unchanged lines in 9 files lost coverage.
• Overall coverage increased (+0.04%) to 67.706%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
common/peerprovider/plugin.go	20	22	90.91%

Files with Coverage Reduction	New Missed Lines	%
service/history/queue/timer_queue_processor_base.go	1	78.23%
service/matching/taskReader.go	2	84.88%
common/task/weighted_round_robin_task_scheduler.go	2	89.05%
service/history/task/transfer_active_task_executor.go	2	72.72%
service/matching/taskListManager.go	2	79.9%
service/matching/matcher.go	2	91.41%
common/task/fifo_task_scheduler.go	3	84.54%
service/history/task/fetcher.go	3	86.6%
service/history/task/transfer_standby_task_executor.go	4	86.63%

Totals
Change from base Build 018f0ea7-c543-4b66-b97e-6fe62553d2d7:	0.04%
Covered Lines:	99179
Relevant Lines:	146484

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💛 - Coveralls