Move the inspect command to "image inspect"

[rumpl]

- What I did

The inspect command needed a bunch of code that was only present in the "internal/commands" package. The patch is big but it's only moving code around:

• cnab.go was split into multiple files:
  • credentials.go -> all things credentials
  • driver/docker.go -> mainly for the driver.Prepare that all the commands use
  • registry.go -> has the method to get insecure registries from engine

- A picture of a cute animal (not mandatory but encouraged)

[codecov[bot]]

Codecov Report

Merging #699 into master will increase coverage by 0.05%. The diff coverage is 74.1%.

@@            Coverage Diff             @@
##           master     #699      +/-   ##
==========================================
+ Coverage   71.28%   71.34%   +0.05%     
==========================================
  Files          56       59       +3     
  Lines        2929     2935       +6     
==========================================
+ Hits         2088     2094       +6     
  Misses        567      567              
  Partials      274      274

Impacted Files	Coverage Δ
internal/commands/run.go	65.71% <100%> (ø)	:arrow_up:
internal/commands/list.go	84.12% <100%> (ø)	:arrow_up:
internal/commands/pull.go	69.23% <100%> (ø)	:arrow_up:
internal/commands/image/inspect.go	73.33% <100%> (ø)
internal/commands/image/tag.go	87.87% <100%> (-1.32%)	:arrow_down:
internal/commands/image/command.go	100% <100%> (ø)	:arrow_up:
internal/commands/image/rm.go	61.29% <100%> (ø)	:arrow_up:
internal/commands/push.go	45.22% <100%> (ø)	:arrow_up:
internal/commands/remove.go	52% <100%> (ø)	:arrow_up:
internal/dockerdesktop.go	46.75% <50%> (ø)
... and 13 more

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