feat: convert entire CLI to clibase (#6491)

I'm sorry.

cli/templateplan.go

@@ -0,0 +1,18 @@
+package cli
+
+import (
+	"github.com/coder/coder/cli/clibase"
+)
+
+func (*RootCmd) templatePlan() *clibase.Cmd {
+	return &clibase.Cmd{
+		Use: "plan <directory>",
+		Middleware: clibase.Chain(
+			clibase.RequireNArgs(1),
+		),
+		Short: "Plan a template push from the current directory",
+		Handler: func(inv *clibase.Invocation) error {
+			return nil
+		},
+	}
+}