Add ShowCluster method implementation to TopologyManager

[alexmasi]

• generalize DeleteCluster to work with non-kind clusters
• ShowCluster status check works for all cluster, cni, and ingress implementations
• topology_names repeated field is currently not used, unclear how to provide this list. will add in a later PR if needed
• Delete/ShowCluster only works for clusters created using CreateCluster. This is due to the extra deployment info stored during cluster creation such as ingress/cni/cluster type in order to perform relevant health checks and deletion

[coveralls]

Pull Request Test Coverage Report for Build 1890356033

• 0 of 87 (0.0%) changed or added relevant lines in 2 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.9%) to 59.241%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
controller/server/main.go	0	37	0.0%
deploy/deploy.go	0	50	0.0%

Files with Coverage Reduction	New Missed Lines	%
controller/server/main.go	2	48.85%

Totals
Change from base Build 1883689241:	-0.9%
Covered Lines:	1779
Relevant Lines:	3003

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💛 - Coveralls