'wdcli backup': Rework backup process

This commit reworks the backup process to dynamically find the list of
components.

internal/component/control/control.go

@@ -0,0 +1,54 @@
+package control
+
+import (
+	"embed"
+
+	"github.com/FAU-CDI/wisski-distillery/internal/component"
+	"github.com/FAU-CDI/wisski-distillery/internal/component/instances"
+	"github.com/FAU-CDI/wisski-distillery/internal/core"
+)
+
+// Control represents the control server
+type Control struct {
+	component.ComponentBase
+
+	Instances *instances.Instances
+
+	ResolverFile string
+}
+
+func (control Control) Name() string {
+	return "dis" // TODO: Rename this to control!
+}
+
+//go:embed all:control control.env
+var resources embed.FS
+
+func (control Control) Stack() component.StackWithResources {
+	return control.ComponentBase.MakeStack(component.StackWithResources{
+		Resources:   resources,
+		ContextPath: "control",
+		EnvPath:     "control.env",
+
+		EnvContext: map[string]string{
+			"VIRTUAL_HOST":      control.Config.DefaultHost(),
+			"LETSENCRYPT_HOST":  control.Config.DefaultSSLHost(),
+			"LETSENCRYPT_EMAIL": control.Config.CertbotEmail,
+
+			"CONFIG_PATH": control.Config.ConfigPath,
+			"DEPLOY_ROOT": control.Config.DeployRoot,
+
+			"GLOBAL_AUTHORIZED_KEYS_FILE": control.Config.GlobalAuthorizedKeysFile,
+			"SELF_OVERRIDES_FILE":         control.Config.SelfOverridesFile,
+		},
+
+		TouchFiles:       []string{control.ResolverFile},
+		CopyContextFiles: []string{core.Executable},
+	})
+}
+
+func (control Control) Context(parent component.InstallationContext) component.InstallationContext {
+	return component.InstallationContext{
+		core.Executable: control.Config.CurrentExecutable(),
+	}
+}