cmd/lncli: move commands and export

We want to export some of our CLI code to re-use in other projects. But
in Golang you cannot import code from a `main` package.
So we need to move the actual code into its own package and only have
the `func main()` in the `main` package.

cmd/commands/watchtower_active.go

@@ -0,0 +1,56 @@
+//go:build watchtowerrpc
+// +build watchtowerrpc
+
+package commands
+
+import (
+	"github.com/lightningnetwork/lnd/lnrpc/watchtowerrpc"
+	"github.com/urfave/cli"
+)
+
+func watchtowerCommands() []cli.Command {
+	return []cli.Command{
+		{
+			Name:     "tower",
+			Usage:    "Interact with the watchtower.",
+			Category: "Watchtower",
+			Subcommands: []cli.Command{
+				towerInfoCommand,
+			},
+		},
+	}
+}
+
+func getWatchtowerClient(ctx *cli.Context) (watchtowerrpc.WatchtowerClient, func()) {
+	conn := getClientConn(ctx, false)
+	cleanup := func() {
+		conn.Close()
+	}
+	return watchtowerrpc.NewWatchtowerClient(conn), cleanup
+}
+
+var towerInfoCommand = cli.Command{
+	Name:   "info",
+	Usage:  "Returns basic information related to the active watchtower.",
+	Action: actionDecorator(towerInfo),
+}
+
+func towerInfo(ctx *cli.Context) error {
+	ctxc := getContext()
+	if ctx.NArg() != 0 || ctx.NumFlags() > 0 {
+		return cli.ShowCommandHelp(ctx, "info")
+	}
+
+	client, cleanup := getWatchtowerClient(ctx)
+	defer cleanup()
+
+	req := &watchtowerrpc.GetInfoRequest{}
+	resp, err := client.GetInfo(ctxc, req)
+	if err != nil {
+		return err
+	}
+
+	printRespJSON(resp)
+
+	return nil
+}