Fee reserve for lightning backends (#557)

* preparing fees

* fee_limit_msat

* await resp result

* clightning

* fix tests

* fix test

* add fee to test

* mypy

* invoice_status

* checking id fix

* fee reserve error message

* only for external payments

lnbits/wallets/lnbits.py

@@ -80,7 +80,7 @@ class LNbitsWallet(Wallet):
 
         return InvoiceResponse(ok, checking_id, payment_request, error_message)
 
-    async def pay_invoice(self, bolt11: str) -> PaymentResponse:
+    async def pay_invoice(self, bolt11: str, fee_limit_msat: int) -> PaymentResponse:
         async with httpx.AsyncClient() as client:
             r = await client.post(
                 url=f"{self.endpoint}/api/v1/payments",