Kpt Deployer applyDir implementation and tests

[felixtran39]

Related: #3904

Description
This is the implementation and tests for the getApplyDir() method of the kpt deployer. This method resolves the package to deploy to the cluster. Users have the option to specify the package themselves in the skaffold config. However if left unspecified, the method will create a hidden directory called .kpt-hydrated and run kpt live init if necessary to create the required template resource (running kpt live init is not done for user specified applyDir even if the template resource is not present).

User facing changes
Users will have the ability to specify their own applyDir in skaffold.yaml.

[codecov]

Codecov Report

Merging #4691 into master will increase coverage by 0.03%.
The diff coverage is 92.59%.

@@            Coverage Diff             @@
##           master    #4691      +/-   ##
==========================================
+ Coverage   73.18%   73.21%   +0.03%     
==========================================
  Files         340      340              
  Lines       13372    13398      +26     
==========================================
+ Hits         9786     9810      +24     
- Misses       2979     2980       +1     
- Partials      607      608       +1     

Impacted Files	Coverage Δ
pkg/skaffold/schema/latest/config.go	100.00% <ø> (ø)
pkg/skaffold/deploy/kpt.go	94.44% <92.59%> (-5.56%)	⬇️

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[MarlonGamez]

This LGTM 👍🏽 For follow up work let's maybe mention that we plan to move away from consuming kpt as a CLI in the future