Refactor CLI and implement fetch-params

[austinabell]

Summary of changes
Changes introduced in this pull request:

• Refactors CLI to setup framework for subcommands

  • Now forest still runs the daemon, but subcommands can be run as forest <cmd> such as here is forest fetch-params ..

• fetch-params command implemented which will fetch params based on the options of command and put into the params cache to be used in proof verification

  • Options are self-documenting by adding the help flag when running the command
  • Verbose flag will use progress bars for the download progress (doesn't always show up cleanly because async logger and the progress bar std out don't always play nicely

The params fetching is all done in parallel and async

Reference issue to close (if applicable)

Closes #508

Other information and links

[StaticallyTypedAnxiety]

Just few suggestions but looks good to me

[ec2]

LGTM. I hear reqwest is pretty heavy. It is recommended to use Surf. Surf has a lot of overlapping libs with Tide since they're built by the same people. Up to you if you think its worth the change though

[austinabell]

LGTM. I hear reqwest is pretty heavy. It is recommended to use Surf. Surf has a lot of overlapping libs with Tide since they're built by the same people. Up to you if you think its worth the change though

Yeah thing was is that it seemed they were still on alpha for using stable futures so didn't seem worth the trial and error, I will play around with it now for a bit though

[austinabell]

I made a bunch of changes so just going to assume reviews invalid @AshantiMutinta @ec2 (sorry they were pretty necessary changes)