Bitcoin Integration in Oisy

[lmuntaner]

This is a Proof Of Concept for the Bitcoin integration. This PoC has been tested against a local bitcoin node following the official IC docs.

Functionality in this PR:

• User sees the Btc address.
• User sees the Btc balance.
• User can make a Btc transaction.

Main questions from this PR:

• Where should the backend endpoints live? Signer canister or Oisy backend?
• There is no endpoint that gives the transaction history. We'll need to find a third party provider with an API.