Serve brand assets as static files via /api/files/v1/static instead of S3

Signed-off-by: Ludovic Vielle <ludovic@probo.com>

pkg/brand/brand.go

@@ -0,0 +1,25 @@
+package brand
+
+import (
+	"embed"
+	"io/fs"
+)
+
+var (
+	//go:embed assets
+	staticAssets embed.FS
+
+	Assets fs.FS
+
+	DefaultPoweredByLogoPath     string = "/api/files/v1/static/probo-gray-small.png"
+	DefaultSenderCompanyLogoPath string = "/api/files/v1/static/probo.png"
+)
+
+func init() {
+	var err error
+
+	Assets, err = fs.Sub(staticAssets, "assets")
+	if err != nil {
+		panic(err)
+	}
+}