add encryption and get page

internal/crypto/decrypt_off.go

@@ -0,0 +1,10 @@
+//go:build !encon
+// +build !encon
+
+package crypto
+
+import "git.loyso.art/frx/eway/internal/entity"
+
+func Decrypt(hexedcipher string) (plaintext string, err error) {
+	return "", entity.SimpleError("this feature turned off")
+}