feat(nargo): Add lsp command to start server that reports no capabilities

[phated]

Description

Problem*

Resolves

Summary*

This PR puts in place the scaffolding for the LSP server logic via nargo_lsp crate and then constructs a Tower stack via the lsp command in nargo_cli. The LSP currently reports no capabilities, but serves as the skeleton to prove that noir-lang/vscode-noir#3 can communicate with it (enable tracing in the options).

The choice to use async-lsp was made because it sets out to solve a bunch of tower-lsp problems.

Documentation

• This PR requires documentation updates when merged.

  • I will submit a noir-lang/docs PR.
  • I will request for and support Dev Rel's help in documenting this PR.

This will add an additional command to the Nargo CLI and we will need to update the docs to mention the VSCode extension that provides the LSP client.

Additional Context

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[kevaundray]

One nit: To be consistent, can you add a header in https://github.com/noir-lang/noir/blob/master/crates/readme.md with the lsp since it a new crate

[phated]

@kevaundray that's done, but the readme.md file is very out of date and still references acvm/acir and is missing other crates.