Become domain-agnostic, with .onion-specific address generation

1) use window.location instead of hardcoded lnurl-pay.me
2) don't use subdomains for address creation on .onion

src/App.svelte

@@ -84,7 +84,11 @@
 	    amount.toFixed(2))+payway.currency.toLowerCase()+"-"):""
     if (account[0]=='+')
       account=account.slice(1)
-    return prefix + account + "@" + payway.id + ".lnurl-pay.me"
+    if (window.location.hostname.endsWith(".onion")) {
+      return prefix + account + "." + payway.id + "@" + window.location.hostname
+    } else {
+      return prefix + account + "@" + payway.id + "." + window.location.hostname
+    }
   }
 
   function genLNURL(payway,account,amount,memo,isEncrypted) {
@@ -100,7 +104,8 @@
     if (memo) {
       params.set("m",toHexString(UTF8.setBytesFromString(memo)))
     }
-    return lnurlEncode("https://lnurl-pay.me/pay?"+params.toString()).toUpperCase()
+    const me = window.location.protocol + "//" + window.location.host
+    return lnurlEncode(me + "/pay?" + params.toString()).toUpperCase()
   }