✨ Extract some commands into kairosctl (#310)

This PR extracts the registration command into a `kairos-register`
binary of its own. The old sub command is kept so users can see a
deprecation notice and adapt for a future release when it's removed. The
version number is shared between binaries.

⚠️ I'm not entirely sure about the gorelease, and would benefit
from a couple of extra 👀 on this, thanks!

relates to kairos-io/kairos#1211

---------

Signed-off-by: Mauro Morales <mauro.morales@spectrocloud.com>
Signed-off-by: Mauro Morales <contact@mauromorales.com>
Signed-off-by: Itxaka <itxaka.garcia@spectrocloud.com>
Signed-off-by: GitHub <noreply@github.com>
Co-authored-by: Dimitris Karakasilis <dimitris@karakasilis.me>
Co-authored-by: Itxaka <itxaka.garcia@spectrocloud.com>
Co-authored-by: ci-robbot [bot] <105103991+ci-robbot@users.noreply.github.com>
Co-authored-by: mudler <mudler@users.noreply.github.com>
Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

cli/kairosctl/main.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/kairos-io/kairos-sdk/bus"
+	iCli "github.com/kairos-io/provider-kairos/internal/cli"
+	"github.com/kairos-io/provider-kairos/internal/provider"
+	"github.com/urfave/cli/v2"
+)
+
+func checkErr(err error) {
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+	os.Exit(0)
+}
+
+func main() {
+	if len(os.Args) >= 2 && bus.IsEventDefined(os.Args[1]) {
+		checkErr(provider.Start())
+	}
+
+	checkErr(Start())
+}
+
+func Start() error {
+	toolName := "kairosctl"
+	name := toolName
+	app := &cli.App{
+		Name:    name,
+		Version: iCli.VERSION,
+		Authors: []*cli.Author{
+			{
+				Name: iCli.Author,
+			},
+		},
+		Copyright: iCli.Author,
+		Commands: []*cli.Command{
+			iCli.RegisterCMD(toolName),
+			iCli.BridgeCMD(toolName),
+			&iCli.GetKubeConfigCMD,
+			&iCli.RoleCMD,
+		},
+	}
+
+	return app.Run(os.Args)
+}