Parse .env or environment variables for RPC auth details

[arik-so]

And possibly for other properties, too, such that not every single launch has to be a super long command, and such that the auth data doesn't get added to the command history.

[TheBlueMatt]

We...don't have an RPC? I'm not sure what auth details we'd want to parse?

[arik-so]

The auth to talk to the bitcoin daemon RPC :)

[TheBlueMatt]

Oh, yea, duh, would be cool to parse the .cookie.

[alecchendev]

Hello! I’m interested in picking up this issue. Worked with Rust a bit in the past but otherwise fairly new. Also new to contributing to open-source.

Here’s what I’m considering for a basic version that parses RPC fields from a .env file:

• In the first argument <bitcoind-rpc-username>:<bitcoind-rpc-password>@<bitcoind-rpc-host>:<bitcoind-rpc-port>, if the user doesn’t include the @, it will parse the string as if it’s just the second half <bitcoind-rpc-host>:<bitcoind-rpc-port>, and check for environment variables and/or look for a .env file in the working directory to parse for the rpc username and password.
• It’ll also print some extra usage information to communicate this option when prompted.

Question: Is there a recommended way for testing changes in this repo?

If anyone has feedback/questions on this it'd be greatly appreciated! I plan to get a PR in for the basic version either tonight or tomorrow sometime, then possibly expand to other arguments after I get that working.

[TheBlueMatt]

Done in #87