Improve skaffold help

[dgageot]

• Change a few descriptions
• Hide find-configs command
• Move debug into the e2e pipelines group

Signed-off-by: David Gageot david@gageot.net

[dgageot]

$ skaffold help
A tool that facilitates continuous development for Kubernetes applications.

End-to-end pipelines:
  run          Run a pipeline
  dev          Run a pipeline in development mode
  debug        Run a pipeline in debug mode

Pipeline building blocks for CI/CD:
  build        Build the artifacts
  deploy       Deploy pre-built artifacts
  delete       Delete the deployed application

Getting started with a new project:
  init         Generate configuration for deploying an application
  fix          Update old configuration to newest schema version

Other Commands:
  completion   Output shell completion for the given shell (bash or zsh)
  config       Interact with the Skaffold configuration
  diagnose     Run a diagnostic on Skaffold
  version      Print the version information

Use "skaffold <command> --help" for more information about a given command.

[codecov]

Codecov Report

Merging #2434 into master will increase coverage by 0.01%.
The diff coverage is 100%.

Impacted Files	Coverage Δ
cmd/skaffold/app/cmd/deploy.go	64.28% <100%> (ø)	⬆️
cmd/skaffold/app/cmd/config.go	100% <100%> (ø)	⬆️
cmd/skaffold/app/cmd/debug.go	50% <100%> (ø)	⬆️
cmd/skaffold/app/cmd/cmd.go	69.36% <100%> (ø)	⬆️
cmd/skaffold/app/cmd/dev.go	25% <100%> (ø)	⬆️
cmd/skaffold/app/cmd/fix.go	67.74% <100%> (ø)	⬆️
cmd/skaffold/man/man.go	89.47% <100%> (+1.23%)	⬆️
cmd/skaffold/app/cmd/find_configs.go	39.58% <100%> (+2.62%)	⬆️
cmd/skaffold/app/cmd/delete.go	55.55% <100%> (ø)	⬆️
cmd/skaffold/app/cmd/run.go	43.75% <100%> (ø)	⬆️
... and 2 more