Add initial tls support

- Uses certificate and key files provided by admin in config
- Let's Encrypt integration planned, but not even close to working
- Initial HTTP3 Support added

web/public/middleware/httpUpgrade.go

@@ -0,0 +1,40 @@
+package webmiddleware
+
+import (
+	"fmt"
+	"net/http"
+
+	"git.mstar.dev/mstar/linstrom/config"
+)
+
+func AddUpgradeHeader(h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch r.ProtoMajor {
+		case 1:
+			// Always offer upgrade to http2
+			headerText := fmt.Sprintf(
+				"h2=\":%d\"; ma=3600",
+				config.GlobalConfig.General.GetFinalPublicPort(),
+			)
+			// Offer upgrade to http3 if enabled
+			if config.GlobalConfig.Experimental.Http3Support && config.GlobalConfig.SSL.HandleSSL {
+				headerText = fmt.Sprintf(
+					"h3=\":%d\"; ma=3600, %s",
+					config.GlobalConfig.General.GetFinalPublicPort(),
+					headerText,
+				)
+			}
+			w.Header().Add("Alt-Svc", headerText)
+		case 2:
+			// Offer upgrade to http3 if enabled
+			if config.GlobalConfig.Experimental.Http3Support && config.GlobalConfig.SSL.HandleSSL {
+				headerText := fmt.Sprintf(
+					"h3=\":%d\"; ma=3600",
+					config.GlobalConfig.General.GetFinalPublicPort(),
+				)
+				w.Header().Add("Alt-Svc", headerText)
+			}
+		}
+		h.ServeHTTP(w, r)
+	})
+}