Add netflow manager (#3398)

* Add netflow manager

* fix linter issues

client/internal/netflow/manager.go

@@ -0,0 +1,48 @@
+package netflow
+
+import (
+	"context"
+	"sync"
+
+	"github.com/netbirdio/netbird/client/internal/netflow/logger"
+	"github.com/netbirdio/netbird/client/internal/netflow/types"
+)
+
+type Manager struct {
+	mux        sync.Mutex
+	logger     types.FlowLogger
+	flowConfig *types.FlowConfig
+}
+
+func NewManager(ctx context.Context) *Manager {
+	return &Manager{
+		logger: logger.New(ctx),
+	}
+}
+
+func (m *Manager) Update(update *types.FlowConfig) error {
+	m.mux.Lock()
+	defer m.mux.Unlock()
+	if update == nil {
+		return nil
+	}
+
+	m.flowConfig = update
+
+	if update.Enabled {
+		m.logger.Enable()
+		return nil
+	}
+
+	m.logger.Disable()
+
+	return nil
+}
+
+func (m *Manager) Close() {
+	m.logger.Close()
+}
+
+func (m *Manager) GetLogger() types.FlowLogger {
+	return m.logger
+}