feat: add basic prometheus metrics integration

internal/proxy/director/director.go

@@ -10,6 +10,7 @@ import (
 	"forge.cadoles.com/Cadoles/go-proxy/wildcard"
 	"forge.cadoles.com/cadoles/bouncer/internal/store"
 	"github.com/pkg/errors"
+	"github.com/prometheus/client_golang/prometheus"
 	"gitlab.com/wpetit/goweb/logger"
 )
 
@@ -59,6 +60,8 @@ MAIN:
 		logger.F("remoteAddr", r.RemoteAddr),
 	)
 
+	metricProxyRequestsTotal.With(prometheus.Labels{metricLabelProxy: string(match.Name)}).Add(1)
+
 	ctx = withProxy(ctx, match)
 
 	layers, err := d.getLayers(ctx, match.Name)