Refactor docker api

[dgageot]

• Introduce a LocalDaemon type that wraps all the local Docker operations.
• Move some of the docker related code to this new type

[codecov-io]

Codecov Report

Merging #1429 into master will decrease coverage by 0.13%.
The diff coverage is 15.31%.

@@            Coverage Diff             @@
##           master    #1429      +/-   ##
==========================================
- Coverage    44.7%   44.56%   -0.14%     
==========================================
  Files         111      112       +1     
  Lines        4579     4593      +14     
==========================================
  Hits         2047     2047              
- Misses       2325     2339      +14     
  Partials      207      207

Impacted Files	Coverage Δ
pkg/skaffold/docker/parse.go	75.11% <0%> (+7.19%)	⬆️
pkg/skaffold/build/local/types.go	0% <0%> (ø)	⬆️
pkg/skaffold/build/local/bazel.go	40% <0%> (+2.5%)	⬆️
pkg/skaffold/docker/remote.go	0% <0%> (ø)
pkg/skaffold/build/local/jib_gradle.go	21.87% <0%> (ø)	⬆️
pkg/skaffold/build/local/jib_maven.go	38.59% <0%> (ø)	⬆️
pkg/skaffold/docker/auth.go	36.36% <25%> (ø)	⬆️
pkg/skaffold/docker/image.go	57.14% <27.9%> (+0.89%)	⬆️
pkg/skaffold/docker/client.go	60.82% <28.57%> (-1.29%)	⬇️
pkg/skaffold/build/local/local.go	54.34% <33.33%> (ø)	⬆️
... and 2 more

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