Refactor Nomad Recovery

from an approach that loaded the runners only once at the startup
to a method that will be repeated i.e. if the Nomad Event Stream connection interrupts.

internal/runner/aws_manager_test.go

@@ -111,5 +111,6 @@ func createBasicEnvironmentMock(id dto.EnvironmentID) *ExecutionEnvironmentMock
 	environment.On("MemoryLimit").Return(uint(0))
 	environment.On("NetworkAccess").Return(false, nil)
 	environment.On("DeleteRunner", mock.AnythingOfType("string")).Return(false)
+	environment.On("ApplyPrewarmingPoolSize").Return(nil)
 	return environment
 }