add simple devnet support

[eramoss]

[aspect]

As an end-user-focused app, why would it need devnet? Just want to understand the reason.

I sort of specifically did not include devnet as when working with devnet one usually would use a raw RK node and cli wallet..

[eramoss]

Im using it for a research and needed the support for devnet to see some statistics and the DAG visualizer, so i thought that some other people would need the same.

its not needed for an end user, but to visualize the behavior while changing the protocol in a simple way (just installing it) is kinda nice.

[aspect]

SGTM!

[eramoss]

Sorry about the lint, i forgot to fmt before