Do a large chunk of the move to go

This commit moves a huge chunk of the code to go. The TODO.md document
indicates what is left to be done.

program.go

@@ -0,0 +1,44 @@
+package wisski_distillery
+
+import (
+	"os/user"
+
+	"github.com/FAU-CDI/wisski-distillery/env"
+	"github.com/tkw1536/goprogram"
+	"github.com/tkw1536/goprogram/exit"
+)
+
+// these define the ggman-specific program types
+// none of these are strictly needed, they're just around for convenience
+type wdcliEnv = *env.Distillery
+type wdcliParameters = env.Params
+type wdcliRequirements = env.Requirements
+type wdCliFlags = struct{}
+
+type Program = goprogram.Program[wdcliEnv, wdcliParameters, wdCliFlags, wdcliRequirements]
+type Command = goprogram.Command[wdcliEnv, wdcliParameters, wdCliFlags, wdcliRequirements]
+type Context = goprogram.Context[wdcliEnv, wdcliParameters, wdCliFlags, wdcliRequirements]
+type Arguments = goprogram.Arguments[wdCliFlags]
+type Description = goprogram.Description[wdCliFlags, wdcliRequirements]
+
+// an error when nor arguments are provided.
+var errUserIsNotRoot = exit.Error{
+	ExitCode: exit.ExitGeneralArguments,
+	Message:  "This command has to be executed as root. The current user is not root.",
+}
+
+func NewProgram() Program {
+	return Program{
+		BeforeCommand: func(context Context, command Command) error {
+			usr, err := user.Current()
+			if err != nil || usr.Uid != "0" || usr.Gid != "0" { // make sure that we are root!
+				return errUserIsNotRoot
+			}
+			return nil
+		},
+
+		NewEnvironment: func(params wdcliParameters, context Context) (e wdcliEnv, err error) {
+			return env.NewDistillery(params, context.Description.Requirements)
+		},
+	}
+}