updater: refactoring and set DNS server correctly

- Fix CLI operation not setting DNS server
- Fix periodic operation not setting DNS server
- Set DNS address for resolution once at start for both CLI and periodic operation
- Inject resolver to each provider instead of creating it within
- Use resolver settings on every call to `.Resolve` method, instead of passing it to constructor
- Move out minServers check from resolver

internal/provider/common/updater.go

@@ -6,6 +6,7 @@ import (
 	"net"
 
 	"github.com/qdm12/gluetun/internal/models"
+	"github.com/qdm12/gluetun/internal/updater/resolver"
 )
 
 var ErrNotEnoughServers = errors.New("not enough servers found")
@@ -15,7 +16,7 @@ type Fetcher interface {
 }
 
 type ParallelResolver interface {
-	Resolve(ctx context.Context, hosts []string, minToFind int) (
+	Resolve(ctx context.Context, settings resolver.ParallelSettings) (
 		hostToIPs map[string][]net.IP, warnings []string, err error)
 }