Maint: interface composition for HTTP proxy loop

- Change SetStatus to ApplyStatus
- Add Runner interface
- Add SettingsGetterSetter alias to state.SettingsGetterSetter

internal/httpproxy/loop.go

@@ -14,13 +14,10 @@ import (
 )
 
 type Looper interface {
-	Run(ctx context.Context, done chan<- struct{})
-	SetStatus(ctx context.Context, status models.LoopStatus) (
-		outcome string, err error)
-	GetStatus() (status models.LoopStatus)
-	GetSettings() (settings configuration.HTTPProxy)
-	SetSettings(ctx context.Context, settings configuration.HTTPProxy) (
-		outcome string)
+	Runner
+	loopstate.Getter
+	loopstate.Applier
+	SettingsGetterSetter
 }
 
 type looper struct {