Add transparent init

[MarlonGamez]

Fixes #1273
Related #4915, #5037, #5141, #5155

Description
Adds the flow that handles users running commands without a skaffold config file being present.

User facing changes (remove if N/A)
If users try to run a command without a skaffold config such as skaffold dev, skaffold will tell them that no config is found, and that it is trying to make one. If it succeeds, it will prompt the user, making sure that they want to continue.

[codecov]

Codecov Report

Merging #5186 (b6c3cd0) into master (a518ce7) will increase coverage by 0.05%.
The diff coverage is 47.82%.

@@            Coverage Diff             @@
##           master    #5186      +/-   ##
==========================================
+ Coverage   71.81%   71.87%   +0.05%     
==========================================
  Files         387      388       +1     
  Lines       13924    14063     +139     
==========================================
+ Hits        10000    10108     +108     
- Misses       3190     3212      +22     
- Partials      734      743       +9     

Impacted Files	Coverage Δ
cmd/skaffold/app/cmd/delete.go	57.14% <0.00%> (ø)
cmd/skaffold/app/cmd/deploy.go	56.52% <0.00%> (ø)
cmd/skaffold/app/cmd/diagnose.go	34.78% <0.00%> (ø)
cmd/skaffold/app/cmd/filter.go	25.58% <0.00%> (ø)
cmd/skaffold/app/cmd/flags.go	87.50% <ø> (ø)
cmd/skaffold/app/cmd/generate_pipeline.go	61.53% <0.00%> (ø)
cmd/skaffold/app/cmd/render.go	46.42% <0.00%> (ø)
cmd/skaffold/app/cmd/test.go	46.66% <0.00%> (ø)
pkg/skaffold/config/options.go	100.00% <ø> (ø)
cmd/skaffold/app/cmd/runner.go	59.37% <37.03%> (-7.30%)	⬇️
... and 24 more

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[gsquared94]

looks good. Should we add two flags:

• one to skip the confirmation ? Would you like to continue? Yes
• one to skip this feature and fail as before

[gsquared94]

lgtm!