"cargo install deno"

[ry]

Currently the deno crate on crates.io is our "core" crate... which is essentially our binding to V8 without any of the ops, typescript, or other high-level functionality that makes up the deno CLI.

Now that we've switched to "cargo build" as our main build frontend (#2608), it's much easier for us to publish the cli crate to crates.io.

I suggest having the deno crate be our cli crate, and have deno_core be the core crate. This would allow people to "cargo install" the executable.

[kt3k]

ref: #3600