migrate from urfave/cli to spf13/cobra

[dragonchaser]

We have replaced urfave/cli by spf13/cobra, because urfave had issues with race conditions and we could not fix them.

Hints for reviewers:

• the PR is huge, but not that huge ("only" 5k lines of change, most of it duplicate refactorings, the rest ist vendoring from spf13/cobra, spf13/viper and spf13/pflag no business logic has been touched)

• displaying help of consumed service commands is tricky, I replace the RunE function in case there is none to make sure that the help is displayed, if the function already has a RunE function, it might be needed to add cmd.Help() there. (replace function: https://github.com/dragonchaser/opencloud/blob/22857e0cdc264701db0fc937b4ef2e595d3f8cd8/opencloud/pkg/command/root.go#L26-L36)

TODO:

• fix https://github.com/dragonchaser/opencloud/blob/22857e0cdc264701db0fc937b4ef2e595d3f8cd8/opencloud/pkg/command/root.go#L26-L36 the nil check is somehow bogus, subcommand help is not displayed
• fix make test-with-race ci hickups... there are actual race conditions
• make ci-green
• please verify that all Required: true in urfave/cli commands are migrated to cobra like:

err := corbraCommandVariable.MarkFlagRequired("<flagname>")
if err != nil {
	fmt.Println(err)
}

• fix Flag("...").Value calls and use type safe cobra substitution, cmd.Flags().GetBool("..."), ...
  i think I replaced all.... but just make sure

• trigger docs team to update docs, because https://github.com/dragonchaser/opencloud/blob/22857e0cdc264701db0fc937b4ef2e595d3f8cd8/opencloud/pkg/command/init.go#L44-L86 the shorthand commands have changed (background: cobra only supports single character shorthands, urfave multi-char shorthands)

• oc init command can not be interrupted with ctrl+c when running interactively without parameters

• make cmd.Context() in cobra inherit from the commands context to accept ctrl+c

[dragonchaser]

There is still an issue with the output of the subcommand usage from opencloud/bin/opencloud all commands are there, can be output with opencloud/bin/opencloud sse --help but running opencloud/bin/opencloud sse no usage is displayed.

Update: dde1a43 fixes the issue

[butonic]

how did this ever work? the flag was registered as restart

[fschade]

w00t 👀