Add describe, delete, and list namespaces (REST) #77

Job	Run time
unit-tests / Type checking (3.9, true)	41s
unit-tests / Unit grpc (3.9)	50s
unit-tests / Type checking (3.9, false)	43s
linting / lint	14s
unit-tests / Unit (3.9)	38s
create-project	0s
cleanup-project / cleanup-project	37s
integration-tests	0s
	3m 43s

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