Github action to deploy devnet (opentensor subtensor instance with a subnet)

[5u6r054]

Have a github action that deploys the opentensor subtensor and runs the initial create subnet:

• This could replace the running "devnet" that have deployed based on / triggered by updates to the main branch of our fork of opentensor/subtensor, so that we control when we redeploy updates to main on our own public devnet / testnet chain
• This should optionally allow for updates to our private devnet code without necessarily starting with a fresh chain.
• This may involve a more volatile private devnet where we run branches other than main when testing changes to the subtensor codebase, and should also optionally allow retaining or starting from a fresh chain database.
• Github action could also provision required infra to run subtensor / devnet on, or that could be handled separately (as with oracle nodes vs. oracle app currently).

[Luka-Loncar]

@5u6r054 hey hey, who should review this ticket?