hil: initial commit

[TheButlah]

Adds an orb-hil binary, to make flashing easy and automated. Its little more than a glorified bash script right now.

Currently it:

• Assumes that it is on the hil and relies on some cli tools provided from the nix shell, like awscli and tar
• Supports flashing from a s3 url or a local tarball

It does not yet support:

• Automatically controlling CTS and RTS pins to reboot orb or trigger recovery mode
• Connecting to serial
• Retrieving s3 urls from a git tag
• Automatically running in response to network events or github runners

[alekseifedotov]

these bash snippets scare me.

[TheButlah]

its not actually bash. This is just a macro that calls std::process:Command. You can read more here: https://docs.rs/cmd_lib/latest/cmd_lib/#why-you-need-this.

I chose to use cli tools to keep it simpler, but nothing prevents us from replacing those runtime dependencies later.

Note that all dependencies are frozen anyway due to the nix config on the HIL.