Add fees (#503)

* wip

* wip

* model

* refactor wallet transactions

* refactor wallet

* sending with fees works and outputs fill up the wallet

* wip work

* ok

* comments

* receive with amount=0

* correctly import postmeltrequest

* fix melt amount

* tests working

* remove mint_loaded decorator in deprecated wallet api

* wallet works with units

* refactor: melt_quote

* fix fees

* add file

* fees for melt inputs

* set default input fee for internal quotes to 0

* fix coinselect

* coin selection working

* yo

* fix all tests

* clean up

* last commit added fees for inputs for melt transactions - this commit adds a blanace too low exception

* fix fee return and melt quote max allowed amount check during creation of melt quote

* clean up code

* add tests for fees

* add melt tests

* update wallet fee information

tests/test_mint_api_deprecated.py

@@ -2,12 +2,12 @@ import httpx
 import pytest
 import pytest_asyncio
 
-from cashu.core.base import (
+from cashu.core.base import Proof
+from cashu.core.models import (
     CheckSpendableRequest_deprecated,
     CheckSpendableResponse_deprecated,
     PostRestoreRequest,
     PostRestoreResponse,
-    Proof,
 )
 from cashu.mint.ledger import Ledger
 from cashu.wallet.crud import bump_secret_derivation