chore: add new skip-unreachable-dirs to not error on init command when a dir can not be read

[renzodavid9]

Fixes: #9164

Description
This PR adds a new flag, --skip-unreachable-dirs to change the behaviour of skaffold init command so it doesn't throw an error when it tries to read a folder for which it doesn't have read permissions, instead it will skip the folder and continue with the initialization.

Test
To test it, using the same repro steps from #9164, now running skaffold init --analyze --skip-unreachable-dirs shouldn't return an error.

[codecov]

Codecov Report

Merging #9163 (fecadca) into main (290280e) will decrease coverage by 6.80%.
Report is 1062 commits behind head on main.
The diff coverage is 48.51%.

@@            Coverage Diff             @@
##             main    #9163      +/-   ##
==========================================
- Coverage   70.48%   63.68%   -6.80%     
==========================================
  Files         515      630     +115     
  Lines       23150    32435    +9285     
==========================================
+ Hits        16317    20657    +4340     
- Misses       5776    10189    +4413     
- Partials     1057     1589     +532     

Files	Coverage Δ
cmd/skaffold/app/cmd/commands.go	97.61% <100.00%> (+0.35%)	⬆️
cmd/skaffold/app/cmd/config.go	100.00% <100.00%> (ø)
cmd/skaffold/app/cmd/config/list.go	65.21% <ø> (ø)
cmd/skaffold/app/cmd/config/set.go	88.72% <ø> (ø)
cmd/skaffold/app/cmd/config/util.go	54.28% <ø> (ø)
cmd/skaffold/app/cmd/credits.go	100.00% <ø> (ø)
cmd/skaffold/app/cmd/debug.go	100.00% <100.00%> (ø)
cmd/skaffold/app/cmd/flags.go	93.00% <100.00%> (+2.18%)	⬆️
cmd/skaffold/app/cmd/generate_pipeline.go	60.00% <ø> (ø)
cmd/skaffold/app/cmd/init.go	100.00% <100.00%> (ø)
... and 41 more

... and 434 files with indirect coverage changes

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