Split code into multiple files

certificates.go

@@ -0,0 +1,16 @@
+package main
+
+import (
+	"crypto/tls"
+	"fmt"
+)
+
+// tlsConfig contains the configuration for generating, serving and cleaning up Let's Encrypt certificates.
+var tlsConfig = &tls.Config{
+	GetCertificate: func(info *tls.ClientHelloInfo) (*tls.Certificate, error) {
+		// TODO: check DNS name & get certificate from Let's Encrypt
+		return nil, fmt.Errorf("NYI")
+	},
+	PreferServerCipherSuites: true,
+	// TODO: optimize cipher suites, minimum TLS version, etc.
+}