cmd: Implement a basic CLI app

[renaynay]

I recommend using cobra as the maintainer is directly affiliated with golang and is generally more active in maintenance as opposed to urfave/cli.

Requirements:

• basic app that interacts with node binary that is able to initialise and start the node, among other commands
  • celestia light init
  • celestia light start
  • celestia full init
  • celestia full start
• ability to take in config file passed in via --config flag on init
• nice grouping / categorisation of flags according to area (e.g. all flags related specifically to light mode are grouped under command ./celestia light --help, as well as other issue areas beyond the node type like metrics, utils, etc.)

Nice to haves:

• ascii art something cool :D maybe this:

  / ____/__  / /__  _____/ /_(_)___ _
 / /   / _ \/ / _ \/ ___/ __/ / __ `/
/ /___/  __/ /  __(__  ) /_/ / /_/ / 
\____/\___/_/\___/____/\__/_/\__,_/  ```
 

[Wondertan]

Let's not call it node, but celestia-node or just celestia.

[Wondertan]

Well, also let's use cobra and viper...

[Wondertan]

Btw, remove the random 'todo' guy you mentioned.

[Wondertan]

@liamsi, yep. Almost hit enter and the page update with the edit ;)

[Wondertan]

@renaynay, @liamsi

IMO, we should have two different binaries for light and full nodes, e.g.

celestia-light
celestia-full

WDYT?

[Wondertan]

Also, instead of bin start let's use a more common bin daemon.

[renaynay]

I am against it. Will be more annoying to maintain and I would like people to think of celestia as the node and then initialise it in either full or light mode. I also am not in favour of bin daemon. It is not more common, especially for blockchain nodes. It's always bin init, bin start. Let's not deviate too much or else we risk confusing average users.

[liamsi]

I'm also in favor of one binary for now. At least I do not see any good reasons for multiple binaries.

I don't think it matters much if the sub-command is called any of run, start, daemon (we could also support aliases if you want: https://github.com/tendermint/tendermint/blob/58a6cfff9a3e370e1bb5eabfd86091e0b1186a22/cmd/tendermint/commands/run_node.go#L104-L105).