Custom request implementation

[minibits-cash]

Implements: #92

Description

This change implements optional customRequest parameter to the CashuMint class and its methods. Every custom request implementation should follow the signature and types for default request method as defined in request.ts.

It then can be passed to the CashuMint class constructor, or optionally to its class methods (following the pattern that is already in place for mintUrl param).

Potential usage is a communication with the mints that might expose their API over other then TLS network connection, such as Tor.

Basic usage by the wallet:

import { CashuMint, } from '@cashu/cashu-ts'
import { torRequest } from '../services'

const getMint = function (mintUrl: string) {
    // ...
    if(mintUrl.includes('.onion')) {        
        const mint = new CashuMint(mintUrl, torRequest)        
    }
    // ...
}

Changes

• Changes are limited to CashuMint class
• Constructor accepts new optional param _customRequest
• Static class methods accept new optional param customRequest
• If custom method is passed it is used to make a request, otherwise default request implementation is used

PR Tasks

• Open PR
• run npm run test --> no failing unit tests
• run npm run format

[gandlafbtc]

Following up on this PR after merging a few other PRs. Sorry for the long wait! Should we rebase this branch and then review it?

[minibits-cash]

Following up on this PR after merging a few other PRs. Sorry for the long wait! Should we rebase this branch and then review it?

I did the rebase of changes on top of the current main branch.

[gandlafbtc]

great work! Maybe even worth to add a section on the readme about it. can be done later