add polling status after every half second for deployment health check

[tejal29]

Should merge after #2847, #2851

This part 2 of #2750.

This only prints deployment status after every 0.5 second.

make install
cd examples/microservices/
skaffold run --default-repo <> --status-check

tejaldesai@@microservices (refactor-break-2)$ skaffold run --default-repo gcr.io/tejal-test --status-check
Generating tags...
 - gcr.io/tejal-test/gcr.io/k8s-skaffold/leeroy-web -> gcr.io/tejal-test/gcr.io/k8s-skaffold/leeroy-web:v0.36.0-225-g0b120a7b
 - gcr.io/tejal-test/gcr.io/k8s-skaffold/leeroy-app -> gcr.io/tejal-test/gcr.io/k8s-skaffold/leeroy-app:v0.36.0-225-g0b120a7b-dirty
Tags generated in 25.993506ms
Checking cache...
 - gcr.io/tejal-test/gcr.io/k8s-skaffold/leeroy-web: Found
 - gcr.io/tejal-test/gcr.io/k8s-skaffold/leeroy-app: Found
Cache check complete in 705.365719ms
Tags used in deployment:
 - gcr.io/tejal-test/gcr.io/k8s-skaffold/leeroy-web -> gcr.io/tejal-test/gcr.io/k8s-skaffold/leeroy-web:v0.36.0-225-g0b120a7b@sha256:b586f4a29d7006e2ad26d973ed4bfbc56c0889176e9ee2db64abe0d81414ee44
 - gcr.io/tejal-test/gcr.io/k8s-skaffold/leeroy-app -> gcr.io/tejal-test/gcr.io/k8s-skaffold/leeroy-app:v0.36.0-225-g0b120a7b-dirty@sha256:87f2e123b1f7a2e30e2eb994046733092f11c78c102c27206064a53ed306b4bb
Starting deploy...
kubectl client version: 1.11+
kubectl version 1.12.0 or greater is recommended for use with Skaffold
 - deployment.apps/leeroy-web created
 - service/leeroy-app created
 - deployment.apps/leeroy-app created
Deploy complete in 1.192437986s
Waiting for deployments to stabilize
 - default:deployment/leeroy-web Waiting for rollout to finish: 0 of 1 updated replicas are available...
Deployments stabilized in 1.484682978s
You can also run [skaffold run --tail] to get the logs
tejaldesai@@microservices (refactor-break-2)$ 

Note: To try this on on our branch, please bump the number of replicas.

[codecov]

Codecov Report

Merging #2813 into master will increase coverage by 0.02%.
The diff coverage is 66.35%.

Impacted Files	Coverage Δ
pkg/skaffold/util/util.go	86.11% <100%> (+0.19%)	⬆️
pkg/skaffold/deploy/status_check.go	54.9% <44.89%> (-9.15%)	⬇️
pkg/skaffold/runner/deploy.go	73.68% <75%> (ø)	⬆️
pkg/skaffold/deploy/resources/resource.go	84.61% <84.61%> (ø)
cmd/skaffold/app/cmd/generate_pipeline.go	50% <0%> (-7.15%)	⬇️
pkg/skaffold/build/cluster/logs.go	15.15% <0%> (-4.85%)	⬇️
pkg/skaffold/deploy/kubectl/visitor.go	92.85% <0%> (-1.27%)	⬇️
...kg/skaffold/generate_pipeline/generate_pipeline.go	39.47% <0%> (-0.79%)	⬇️
pkg/skaffold/generate_pipeline/tasks.go	76.4% <0%> (-0.52%)	⬇️
... and 17 more