feat: add strike backend

[im-adithya]

Description

Adds support for Strike as a backend for NWC.

Supports get_balance, get_info, make_invoice, pay_invoice

Tested using alby-js-sdk

[frnandu]

We should drop this, since any update or change should be done from now on in https://github.com/getAlby/nwc.getalby.com/tree/feat/strike, since that one will be deployed on https://strike-nwc.albylabs.com/

[rolznz]

I agree, closing for now CC @im-adithya