Document the steps required to connect Forest to a local dev network

[lemmih]

Issue summary

Rough notes for running a dev-net can be found here: https://github.com/ChainSafe/forest/blob/main/documentation/src/developer_documentation/devnet_notes.md

Short summary:

• Build lotus in 2k mode.
• Generate network parameters in the localnet.json and devgen.car files.
• Run the lotus node.
• Run the lotus miner.

Forest should be able to connect to this network if our configuration was flexible enough. In particular, we need a way to set the genesis bytes, the bootstrap peers, the network name, etc.

Tasks:

• Extend the Forest configuration to capture everything needed to connect to a local network.
• Fix occurrences in the source code that assume the network must be either Mainnet or Calibnet.
• Document the steps requires to run a local network with lotus, lotus-miner, and forest.

Other information and links