Add faucet for miden-node

[phklive]

The Miden node generates 2 accounts by default at genesis:

• a Faucet account
• a regular account

We need to make the faucet available and usable on node spin-up, this would enable request of funds and testing of tx's from users of the network.

In this PR I propose to add a new crate called faucet to the node workspace and use actix-web to create a web-server that will serve html, css and js static files.

The faucet receives requests of funds through an endpoint where users on the frontend pass their AccountId. The server responds with the note generated by the tx. The end user is then able to import this newly received note into their client and consume it locally.

closes: #215

[bobbinth]

Awesome! One question: would it make sense to add this feature into the miden-node crate so that the faucet could be started together with the node (maybe using a command line arg).

One benefit of this is fewer components for users to manage. The downside is potential extra complexity in the node. I'm not sure how these balance each other.