hooks: implement for helm and kustomize deployers

[gsquared94]

Fixes: #6420
Related: #1441

Description

This PR implements lifecycle hooks for helm and kustomize deployers.

User facing changes (remove if N/A)

Users can specify hooks definition for helm or kustomize deployers

deploy:
  helm:
    releases:
    - name: skaffold-helm
      chartPath: skaffold-helm
      artifactOverrides:
        image: gcr.io/k8s-skaffold/skaffold-helm
    hooks:
      before:
        - host:
            command: ["sh", "-c", "echo pre-deploy host hook running on $(hostname)!"]
            os: [darwin, linux]
      after:
        - container:
            command: ["sh", "-c", "echo post-deploy container hook running on $(hostname)!"]
            containerName: skaffold-helm*
            podName: skaffold-helm*

[codecov]

Codecov Report

Merging #6454 (8bcd0e1) into main (7d7de48) will increase coverage by 0.02%.
The diff coverage is 95.12%.

@@            Coverage Diff             @@
##             main    #6454      +/-   ##
==========================================
+ Coverage   70.29%   70.32%   +0.02%     
==========================================
  Files         510      511       +1     
  Lines       22976    23020      +44     
==========================================
+ Hits        16152    16189      +37     
- Misses       5769     5773       +4     
- Partials     1055     1058       +3     

Impacted Files	Coverage Δ
pkg/skaffold/schema/latest/v1/config.go	62.16% <ø> (ø)
pkg/skaffold/hooks/types.go	75.00% <75.00%> (ø)
pkg/skaffold/deploy/helm/deploy.go	77.91% <100.00%> (+1.09%)	⬆️
pkg/skaffold/deploy/kubectl/kubectl.go	64.07% <100.00%> (ø)
pkg/skaffold/deploy/kustomize/kustomize.go	74.51% <100.00%> (+1.98%)	⬆️
pkg/skaffold/hooks/deploy.go	85.71% <100.00%> (ø)
pkg/skaffold/runner/v1/deploy.go	72.22% <0.00%> (-2.07%)	⬇️
pkg/skaffold/docker/image.go	65.56% <0.00%> (-1.00%)	⬇️
cmd/skaffold/app/cmd/flags.go	90.81% <0.00%> (ø)
pkg/skaffold/config/options.go	100.00% <0.00%> (ø)
... and 3 more

---

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[MarlonGamez]

LGTM 👍🏼

[glennpratt]

@gsquared94 it appears 9327776 broke some Travis-CI stages.