Maint: dns package state rework

- Interface composition with loopstate interfaces
- Use loopstate.Manager
- Create dns/state package for handling settings

internal/dns/status.go

@@ -6,23 +6,11 @@ import (
 	"github.com/qdm12/gluetun/internal/models"
 )
 
-type StatusGetterApplier interface {
-	StatusGetter
-	StatusApplier
-}
-
-type StatusGetter interface {
-	GetStatus() (status models.LoopStatus)
-}
-
-func (l *Loop) GetStatus() (status models.LoopStatus) { return l.state.GetStatus() }
-
-type StatusApplier interface {
-	ApplyStatus(ctx context.Context, status models.LoopStatus) (
-		outcome string, err error)
+func (l *Loop) GetStatus() (status models.LoopStatus) {
+	return l.statusManager.GetStatus()
 }
 
 func (l *Loop) ApplyStatus(ctx context.Context, status models.LoopStatus) (
 	outcome string, err error) {
-	return l.state.ApplyStatus(ctx, status)
+	return l.statusManager.ApplyStatus(ctx, status)
 }