Document the "zk lightnet" subcommand at docs.minaprotocol.com

[shimkiv]

Somewhere under the https://docs.minaprotocol.com/zkapps about local development and testing.

Sub-commands added to zkApp CLI in:
o1-labs/zkapp-cli#510

[barriebyron]

@shimkiv can you provide some example commands with a nice overview of a typical test environment for our developers?
The default values are good for a single node, etc etc
Thank you!

[shimkiv]

@barriebyron most of the time the defaults should be used.
Examples of commands configuration and use cases I'll add later.

[shimkiv]

User Stories for lightnet Docs Internal docs.

[barriebyron]

notes from an earlier convo with @garwalsh

• I'll start with review of Serhii's awesome user stories and then audit the docs for variations on current testing to see what sections of the docs need updating to use the zk lightnet commands
• Create a draft PR to stage some content that Gar can help me place in the right product-focused docs