Add TopologyManager DeleteCluster method

[alexmasi]

• method only supports kind clusters as of now
• method returns appropriate grpc status codes to indicate if the cluster name does not exist or is not a kind cluster
• fix logging

Tested: end-to-end with instance manager

[coveralls]

Pull Request Test Coverage Report for Build 1883658971

• 0 of 41 (0.0%) changed or added relevant lines in 2 files are covered.
• 111 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.6%) to 60.183%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
deploy/deploy.go	0	4	0.0%
controller/server/main.go	0	37	0.0%

Files with Coverage Reduction	New Missed Lines	%
topo/topo.go	111	40.88%

Totals
Change from base Build 1866422131:	-0.6%
Covered Lines:	1779
Relevant Lines:	2956

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💛 - Coveralls